Dangerous Dave fan page: the code, the HD engine and Aviv's tool-assisted run

1. From the start (2,8) jump up-right onto the stepped platforms. Climb them left to right: the low wall (row 7, columns 4-7), then the pillar at (9,5).
2. Jump up onto the pillar at (11,3) and take the trophy at (11,2) (t186).
3. Keep going right and drop onto the long platform at row 7 (columns 11-16).
4. At its right end hop off into the narrow shaft (column 17), and hold ← as you fall so Dave hugs the shaft's left wall.
5. Land on the floor and walk left under the platform into the door at (12,8) (t414).

Trick: the shaft hop (at the right end of the long platform, (16,6), x 263).

• The keys: Up for 1 tick at t297, Right for 3 ticks, nothing, then ← for 1 tick at t329 as Dave clears the ledge (y 138); the Left is kept while falling.
• Window: the Up press -1..0 (2 ticks: frame-perfect); the Left press 0 only. Pressing Left 2 ticks late costs 3 ticks, 5 late costs 9, and 2 or 5 early costs 15.
• Human version: walk off the ledge end instead of hopping (Right held over t297-301), then the run's keys: door at 420, 6 ticks later.
• Holding instead of tapping: the whole level replays identically with every tap held.

1. From the start (1,8) climb the left side to the top corridor, (5,1).
2. Drop into the box at columns 9-14 and take the trophy at (13,5) (t353).
3. Climb back out and go east along the top corridors to column 29.
4. Come back west along row 3 to column 25 and snake down through the middle: down at column 23 to the bottom row, then up and down twice over the blocks between columns 25 and 34.
5. Climb at column 35 to row 3, step west to column 32, and climb to the top corridor (row 1).
6. Run straight east above the water pool to the door at (47,1) (t1834).

The one release that matters: Right let go for 1 tick at t208, the first falling tick after the jump into the top corridor (about (6,1), x 96). Dave drifts 1 px less, and the run's later jumps depend on that pixel (holding instead gives deaths later, the first at t874).

• Making the release 2 or 3 ticks long also fails (3 deaths).
• No forgiving version found.

Every other tap in level 2 can be held.

1. From the start (2,5) hop right along the long corridor (rows 3-5). The floor of row 5 has hazard tiles, so the run hops almost all the way.
2. On the way it takes the gun at (10,3) in a hop (t132) and shoots both saucers in the corridor (Ctrl while hopping; they die at t433 and t933).
3. Near the end, drop straight down the pit at columns 66-67. Its floor holds the jetpack (66,8) and the trophy (67,8), and both its walls are hazards. Take both and light the jetpack at once (t1448).
4. Fly straight up the shaft, step right and jump into the door at (69,1) (t1539).

Dave drops into the pit and presses the jetpack key just before the pickup.

Trick: catching the jetpack in the pit.

• The keys: →+↓ for 2 ticks at the pit's edge (t1434), Up while falling, Alt pressed at t1446 and released at t1447, the very tick Dave touches the jetpack and trophy (y 128). The jetpack lights at once and he flies up.
• Window: 0. Moving the Alt press by +-1 or +-2, or the Up at t1436 by +-2, breaks the run.
• Human version: let Dave land on the pit floor first; landing takes the jetpack and trophy too. Then press Alt and fly up until y 67, then the run's last keys: door at 1572, 33 ticks later.
• The last Alt before the door (t1533): 1 tick later costs 1 tick; 1 tick earlier misses the door.
• Holding instead of tapping: identical run.

1. From the start (1,5) run and hop east through the whole level, about 70 columns, past the saucer screen without touching the saucer.
2. Climb the left side of the last maze and take the jetpack at (69,4) (t1636).
3. Die on purpose: jump up into the hazard tile beside the jetpack's pocket, at (67,2) (t1768). The restart puts Dave back at the start, a few columns from the trophy. He keeps the jetpack and its full fuel.
4. After the restart (Right held through the wait), go east along the bottom rows to column 12 and fly up to row 2. Go west along rows 2-3 to column 2 and up into the top-left room. Take the trophy at (6,1) (t2549).
5. Fly east along the upper corridors, in short bursts with Alt switching on and off to save fuel, past the saucer again.
6. On the last screen move along the floor. Then climb the right-hand shaft at column 91; the fuel runs out at (92,3), just short of the top. Jump into the door at (97,2) (t4307).

Dave takes the jetpack, dies on purpose and keeps the fuel.

The one release that matters: Alt let go for 1 tick at t3894, between two →+Alt presses (t3893, t3895), at (75,7) while falling. It is a 2-tick jetpack hover that lands Dave 2 ticks later.

• No hover, a 3-tick hover and a 4-tick hover all fail with the run's later keys.
• Human version (replaces this release and the pulsing on the last floor):
  1. From t3893 hold →: walk along the floor to column 91 (x 1456).
  2. Alt; hold ↑ until row 3 (y 64).
  3. Right until x 1474, over the block at (92,4).
  4. Alt (jetpack off), wait 3 ticks to land.
  5. Hold ↑+→ into the door.

Door at 4447, 140 ticks later, with only the planned life lost.

• Hopping along the floor instead of walking gets stuck on a ledge (x 1314).

The deliberate death. Dying later than the run does breaks its keys for the way back: the saucer on screen 2 is dodged by timing. A death 5 or 20 ticks later, with the rest of the keys unchanged, ends with a second death at t2968 or t2974. A player dodges that saucer by eye.

1. From the start (2,8) climb the trees at the left edge to the top of the map. Run and hop east above the play area, where nothing can touch Dave, and drop back in near column 24 (t429).
2. Work east through rows 1-3 and take the jetpack at (37,3) (t645). Fly east and take the trophy at (47,2) (t790).
3. Turn back west into a saucer's shot (t827). Dying keeps the trophy, and the restart puts Dave at the start (2,8) with the jetpack and its fuel (50 units left).
4. After the restart (t1126) jump up-left and light the jetpack. Fly straight up column 1 to above the map.
5. Fly west above the map, switch the jetpack off over x 10, and land on top of the map at the top-left corner.
6. Jump up-left off the edge. The jump wraps Dave to the band below the map; at the top of the arc (y 224) light the jetpack.
7. Fly west to x -75 (5 columns left of the level) and fly up. Left of the edge the game reads the map from its right end, one row up. At (virtual) row 4 Dave touches the level's real door, (97,3) at the far right: level done (t1521).

The normal route takes the trophy, then flies to the door at the far right.

Windows (the run):

• the turn back into the shot (Left at t791, at (46,2)): -1..0. Turning 1-3 ticks later dies 1-2 ticks later, and the run's fixed restart key then misses.
• the first key after the restart (↑+← at t1126): every tick of delay costs 1 tick at the door (+1 gives 1522, +3 gives 1524). Easy.
• lighting the jetpack in the first jump after the restart: no slack in the run, but Dave still reaches the top for shifts of +-2.
• landing on top (Alt t1299-1300, let go at t1301 over x 10): no slack in the run.
• lighting the jetpack at the top of the arc (←+Alt t1358-1359): -6..0 (7 ticks: hard).
• the column (Up at t1391, x -75): 0..+4 reach the door (x -75 to -79), each tick later costing 1 tick (5 ticks: very hard). At x -74 or x -80 Dave misses the door. Dave is off-screen here, so count ticks or watch the fuel bar.

Human version: door at 1522, 1 tick later. From t1293 (Dave above the map, flying west at y 3):

1. hold ← until x <= 12;
2. Alt for 2 ticks;
3. hold ↑+← until the jump starts;
4. hold ← until the arc's top (y <= 224);
5. Alt for 2 ticks;
6. hold ← until x <= -77;
7. hold ↑.

Starting this script right at the restart (↑+← 25 ticks, Left 30, Alt 2, Up until y <= 3, then the steps above) gives door 1524, +3. Dying 2 ticks later and pressing the restart key 1 tick later gives door 1522.

Why that trophy exists. Left of column 0 the game reads the map one row up, from its right end. For row 0, "one row up" is outside the map: the values just before it, where the game keeps the level's monster paths. On every level the last of those values happens to be the code the game uses for a trophy. So at (virtual) column -1 of row 0, a few pixels off the left edge of the first screen, the game finds a trophy: the "phantom trophy". Dave takes it rising at x -46..-43, at y 31.

Step by step (ticks of the run):

1. Jetpack and gun.
   • From the start (2,8) jump up-right onto the jetpack at (6,6) (t59).
   • Jump up-left; Alt (pressed t77, let go t78) lights the jetpack. Rise to the gun at (3,5) (t80).
   • Alt again (let go t97): jetpack off. Drop to the bottom row.
2. Shoot saucer 1. While falling past (6,7), →+Ctrl at t121 for 4 ticks. The shot kills saucer 1 at t149. Window -1..+3 (5 ticks: very hard); 2-3 ticks early, Dave dies at t219.
3. Along the bottom row. Land at (6,8) (t132); Alt (let go t132) lights the jetpack. Move right along row 8 to x 319 (columns 19-20) by t361.
   • The run does this with a 6-tick pulse that switches the jetpack on and off to save fuel: Alt+→, Right, Alt+→, Left, nothing, nothing. It is not humanly repeatable.
   • A player can simply hold → with the jetpack on. Dave reaches x 319 at the same tick (t361), and the door comes at the same tick, 1340. Fuel is 45 instead of 54 at t361, which is enough.
4. Up the shaft. Hold ↑ (t361): fly up the shaft at columns 19-20 to row 3, 12 px left, then up to row 1 (t482, x 307, y 35).
5. West along row 1. Hold ← (t482-739): fly west at y 35 to x 65. The screen scrolls back to the first screen at t518-532.
6. Up through the door tile. At x 65 hold ↑ (t739). Dave flies up through the door (4,0): until you hold the trophy, the door is empty space. He is above the map at t759.
   • Window for the run: -3..0 (4 ticks).
   • The door tile lets Dave through for -3..+3 (7 ticks: hard).
7. West above the map. Hold ← at y 3 (t771-820) to x 16. ←+Alt (t820-821), let go at t822: the jetpack switches off and Dave lands on top of the map at x 14 (t823).
8. Jump left over the edge. ↑+← (t825, 4 ticks), then ←.
   • The first rising step of a jump from the top of the map wraps Dave to y 253, below the map. So he is not above the map when he passes x < 2, where the game would warp.
   • The arc carries him left past the edge (x < 0 from about t832).
9. Light the jetpack at the top of the arc. ←+Alt at t878-879 (x -38..-40, y 224).
   • Window -6..+1 (8 ticks: hard).
   • Later than +1, Dave drifts too far left and misses the column.
10. The column. Fly left to x -46 (t886) and hold ↑.
    • Window: Up at x -43..-46 (0..3 ticks early), which is 4 ticks: very hard. At x -47..-49 Dave misses the trophy.
    • Dave is off-screen here: the picture shows the empty start room and only the fuel bar moves. Count ticks from the light, or watch the bar.
    • Dave flies up for 192 ticks through the band below the map and into the virtual column. There the game reads column 98 of the level, a column of gems worth 4,500 points (an extra life in our run).
11. The phantom trophy. At y 31 Dave cannot rise further: the next value up acts as a ceiling for the jetpack. ↑+Alt for 1 tick (t1078), then let go. At t1080 the trophy is taken ("GO THRU THE DOOR!") and the jetpack switches off.
    • Window for the run 0..+1 (2 ticks: frame-perfect); for the trophy alone 0..+3.
    • Earlier, Dave drops before he reaches the trophy.
12. Fall back through the wrap. Dave falls straight down at x -46; sideways drift is blocked until y 170.
    • Hold → from t1209. The fall drifts right, Dave drops out of the bottom, wraps to the top and lands on top of the map at x 43 (t1305).
    • Window -20..+5 (26 ticks: easy).
    • He must land at x 2 or more, or the game warps.
13. Into the door. Move right on top to x 59 (the run uses short Alt+→ jetpack pulses along the top). Hold Alt and let go over x 59: Dave drops into the door tile (4,0) and the level ends at t1340.
    • Letting go 1-3 ticks late costs 1-3 ticks (x 60-62).
    • Letting go 1-2 ticks early leaves Dave standing on the border; he walks in at +19/+20 ticks.

Human version. Flying instead of pulsing (step 3) is the only change it needs: door at 1340. The other steps go by position. The hard ones are step 10 (a 4-pixel column, off-screen) and step 11 (let go of Alt just as Dave stops at y 31).

1. From the start (1,2) drop onto the gun at (4,6) (t48) and shoot saucer 1 at once (it dies at t55).
2. Hop the pillars east with ↑+→ held, shooting on the move: saucer 2 dies at t261, saucer 3 at t790.
3. Keep hopping east across the scrolls (saucer 4 dies at t1040) and climb to the trophy at (77,2) by way of (76,1) (t1717).
4. Turn back west with ↑+← and drop down to the door at (58,3) (t2076).

No jetpack, no deaths. Dave kills all four saucers.

Windows (the most forgiving level):

• the shot at t692 (→+Ctrl, 9 ticks): -3..+3 (at least 7 ticks: hard or easier);
• the shooting stretch from t1092: 0..+3 (3 ticks early gives two deaths);
• the turn back after the trophy (↑+← at t1727): -3..+3.

Holding instead of tapping: identical run. In practice the level is held keys and well-timed shots.

1. From the start (2,8) go east across the lower-left rooms and up the steps to (28,2). Jump onto the jetpack at (30,1) (t546).
2. Cancel the jump. Alt right at the pickup lights the jetpack for 2 ticks (t546-547), and a second Alt switches it off. That cancels the rest of the jump's rise, so Dave drops at once, left of the block below.
3. Fall down the middle to just above the floor hole at (34-35,9). Both its neighbours, (33,9) and (36,9), are hazards. The run hovers 2 ticks with the jetpack over the edge (Alt at t661 on, Alt at t664 off) to enter the hole at the right pixel.
4. Fall out of the bottom; Dave comes back in at the top of the same columns, through the gap in the ceiling at (34-35,0) (t786-794), and lands on the corridor floor near (37,2).
5. Jetpack on (t829). Fly east along the corridor: row 2, then row 1 after column 60, landing on blocks now and then to save fuel and passing two saucers. Trophy at (81,1) (t1564); door at (97,2) (t1825), with 2 fuel units left.

The releases that matter: Right let go for 2 ticks at t435-436 (end of a jump at about (23,4)), and for 1 tick at t666 (right after the hover).

Windows: none near the hole.

• Moving the 2-tick hover by -3..-1 or +2/+3 kills Dave in the hazards beside the hole (t664-667).
• Moving the jetpack tap after the pickup by -1..+3 breaks the run.
• Changing either release (1, 3 or 4 ticks; holding) breaks the run. No forgiving version was found for them.

Human version for the hole (it works):

1. After the screen scroll ends (no keys are read during it), press Alt.
2. Hold → until Dave stops at the wall (x 547).
3. Hold ↓ until the jetpack switches itself off inside the hole (y 170).
4. Let go. Dave falls out of the bottom, comes in through the ceiling gap and lands in the corridor at t848. The run is there at t825: about 83 ticks later at the corridor's start.

The corridor's two saucers must then be dodged by eye: a blind flight script dies by the trophy at t1700.

1. From the start (6,1), top left, drop and hop east (first scroll at t195).
2. Jump to (20,3), walk off the ledge at (22,4) and drift down into the hole at columns 25-26 of the bottom row. All the floor around it is hazard; the run steers the last pixels with 1-tick Left/Right taps at t321-322 and t379-382.
3. Fall out of the bottom and land on top of the map (t503, x 525). Walk right, then jump along the top with up-right (keypad 9) to column 46.
4. Drop into the open part of the top row (columns 47-67) and straight down onto the trophy at (47,3) (t808).
5. Hop east over the pillars of row 8 with up-right, then go up the right wall to (75,3)-(76,2).
6. Jump back west with up-left (keypad 7), above the map between the stones of row 2 (columns 75, 70, 65). Drop onto the door at (59,3) (t1790).

The route uses the hole, the walk on top, the drop onto the trophy and the jumps back west.

The release that matters: Right let go for 1 tick at t250, the first falling tick after the jump to (20,3) (x 322).

Windows:

• Down onto the trophy (t771): at least -3..+3, with the same run.
• The last up-left+Down into the door (t1658): 0..+6 (+6 costs 3 ticks); earlier misses the door.

Human version: full reactive script, door at 1935 (+145), no lives lost.

1. From t211 hold → until x >= 405 (over the floor hole).
2. Hold ↓ until Dave is below the map (y >= 176).
3. No keys until he stands on top of the map.
4. Hold up-right (keypad 9) until x >= 750, past column 46. At x 746 Dave would stand on the edge.
5. Hold ↓ until the trophy.
6. Right to x 773; Down until standing. Then 9 until x >= 896; Down until standing. Then 9 until x >= 1204 (the right wall).
7. Up for 49 ticks, then 9 for 47 ticks. Then up-left (keypad 7) until x <= 1122, and Down for 14 ticks. Then 7 until x <= 1042, and Down for 14 ticks. Then 7+Down until the door.

The fixed holds (49, 47, 14 ticks) are the run's durations; a player does them by eye.

1. From the start (2,8) climb the steps of the first screen to row 2 (columns 4-6). Go right and down to the floor near column 10. This part holds the 2-tick release at t121-122.
2. Drop through the only safe floor hole, (10,9) (t352-379). Fall out of the bottom and land on top of the map at column 15 (t456).
3. Jump along the top with ↑+→ (each jump wraps below the map and back) to column 62. Drop into the one-tile gap at (62,0) (t1386).
4. Take the jetpack at (64,6) (t1498) and fly back up the column-62 shaft and out (t1597). Saucer 2 crosses that shaft.
5. Jump along the top to column 96, drop in at (96,0) (t2207), take the trophy at (97,8) (t2320) and fly back out (t2432).
6. Jump along the top west to column 62, drop in again (t3069), and go down to the floor and left.
7. The gun seam. At the seam between a brick and a fire tile, (49|50,7), jump straight up from x 796. Two 1-tick Left taps in the jump make Dave rise at x 792. One of his head points is then on the brick and the other on the fire, and the game treats that pair as neither wall nor hazard. So he rises through row 7 into the gun at (50,6) (t3440).
8. Jetpack on; saucer 1 dies at t3525. Fly west along the floor and up into the door room, to the door at (15,1) (t4118).

The route uses the floor hole, the top of the map and the gun seam.

The release that matters: Right let go for 2 ticks at t121-122, at the top of a jump at about (3,4) (x 60, y 80).

• A 3-tick release gives the same run.
• 1, 5 or 6 ticks, a 4-tick release starting a tick early, or holding: Dave dies at t270-271 in the fire.
• Window 2-3 ticks: frame-perfect. No forgiving version found in 7 tries, including holding and walking back to the run's spot before its next jump.

Pixel windows (from the game's collision rules; our probes: x 794 takes the gun, x 796 burns; x 991 drops into the gap, x 1001 lands beside it):

• the gun seam: x 791-795. x 794 also takes the gun; x 796 burns.
• the one-tile gap: x 987-999.
• Both work as tricks, but the run's later keys need its own x.
• The floor hole: the Right at t338 can come 3 ticks earlier with the same run; 3 ticks later Dave still drops through, but the later keys miss.

Every window and human version here was measured with 233 short replays of the run's keys in our C translation of the game; no new searches were run.