TASVideos

Tool-assisted game movies
When human skills are just not enough

Game Resources / DOS / Jazz Jackrabbit

Speeds of motion:

Motion Pixels per frame (no speed bonus) Pixels per frame (speed bonus)
Normal running 6 12
Running uphill 5 12
Hurting horizontal 4 4
Jumping/falling vertical 6 9
Hoverboard max horizontal 6 12
Hoverboard max vertical 3 5[2]
Pipe horizontal 10 (unknown)
Pipe up 6 12?
Pipe up from springboard 13 13?
Pipe down (falling speed) (falling speed)
Swimming horizontal 2 4
Swimming up 3 4
Sinking in water 0, 2[3] 0, 3[3]
Swimming down 2, 3[3] 2, 4[3]

[2] 6 when in influence of vertical "magnetic field".

[3] Alternates between these values.

Note that many bumps and height changes in upward direction (even slight!) count as upslope (especially end of those sagging bridges).

Note that also glancing blows to edges slow Jazz down to 5 pixels (ignored with speed bonus) per frame.

If you get yourself into a wall, you will get stuck, so no zipping.

Controls:

Acceleration and deceleration have frame rules, which causes how controls work change from frame to frame. Worse yet, there are multiple cycles in there, and shortest of those is 2 frames (without speed shoes). This makes controls bit clumsy for TAS.

Also, sometimes the order buttons are pressed within single video frame affects things.

Firing every second frame

Standard 30Hz autofire trick works with every weapon except TNT (because it autoswitches when fired). Note that in some cases input phase changes mid-firing, in these cases button must be held/released for two frames to fire at fastest possible rate.

RF missile damage

RF missile launcher shoots two missiles at once. If both hit, it will do more damage than blaster or toaster (enough to kill normal enemies on turbo difficulty). Useful to kill some enemies in tight spaces when there's no time for double shot.

Also, RF missiles fire a bit upwards and downwards, which is sometimes handy for taking out some enemies (like those electric eye enemies in Tubelectric level 2 (fourth level of 1st episode.

Bird helpers

Bird helpers fly near Jazz and will shoot at enemies if they are on screen. They shoot roughly every 16 frames and shoot 2 projectiles at a time that do 1 damage each. Birds will save an amount of frames on boss fights proportional to the boss's health, so the cost of bringing one into the battle should be weighed.

Shield knockout glitch

A basic function of the shield is to eliminate destroyable non-boss enemies when they come into contact with Jazz while using up part of the shield's power. However, if on that same contact frame the enemy is also hit with a projectile, the enemy will be destroyed (explosion rather than knockout animation) and the shield will not be expended. Confirmed to work with 4-hit shields, will probably work with 1-hit shields as well.

Upslope without speed loss

If one contacts upslope without speed bonus when action timer is divisible by 8, one can immediately jump off with no time loss.

If this is not possible, maximizing atimer mod 8 on contact minimizes the time loss, which is:

  8 - atimer%8  (pixels).

Pipe specials:

Simultaneously on ground and in air

This is to be avoided. By hitting the border between level ground and downslope, the game can get confused and not let you jump. One place this can happen is after the first drop to the wide hole in Diamondus level 1 (the first level of episode 1).

Short springboard jump

In contrast to previous, this may be useful. Depending on the frame parity of the beginning of the spring jump, the jump height will vary by ~13 pixels. Useful in Tubelectric 2 to avoid hitting the electric eyes enemy on top of blue springboard jump (also useful if height of jump is limiting factor in speed).

Spring jump cancel

When passing through a "bridge" tile (something that can be stood upon yet also passed through from the bottom), hold Alt+Down to stop the spring jump and transition into a normal jump.

Downslope with speed bonus

Attaching to a downslope from a freefall with a speed boost can be tricky due to the asymmetry in the velocity components (peaking at hspeed = 12 pixels/f and vspeed = 9 pixels/f). There are multiple "planes" (x+y or y-x depending on direction) Jazz can attach to (at least 4). And only the bottommost is stable.

Shooting the exit sign

Jazz should be as close to exit sign as possible when it gets shot. The reason is that exit sign will be scrolled to center of screen before score countdown starts, and this scrolling is slow. The time difference this makes can be half a second.

This is also applicable to episode bosses (they too will scroll something to center of the screen after they finish blowing up (and one presumably needs to have further input).

Score countdown cancel

When score countdown has lasted long enough (when counting down from 300, the score is about 27 at this point), firing weapon will cancel the countdown. Saves about 1.5 seconds per countdown.

Getting damage-knocked forward

If you turn just before getting hit, you will get knocked forward. The damage knockback speed is 4 and acceleration will resume from that value.

Relative to full running speed, taking damage is 9-10 frame loss if Jazz has no speed bonus, and 18-19 frame loss with speed bonus.

Taking damage is really to be avoided if at all possible if something blocks the arc Jazz flies when taking damage (because the speed will be zeroed) or if taking damage will cause bigger fall (just the time loss).

Hoverboard damage boost glitch

If hoverboarding Jazz is hurt and then drifts into a bounce pad during hurtlock, he will bounce upwards at an enormous and constant speed of 13 pixels/f, greatly exceeding the normal vertical speed of 3 pixels/f. The downsides of this glitch are the inability to stop and loss of control of hspeed. The speed boost ends either immediately after hitting a wall/ceiling or a short time after a glancing blow.

TNT exit trick

In some levels (like Holidaus 2 in Holiday Hare '94), it might be possible to get fairly close to exit sign with some parts of level still remaining. If one uses TNT ammo there, it might be possible to hit the exit sign, triggering the level end sequence (the scroll will be long however).

Magnets

Magnets are a gimmick that appear in Letni, Scraparap, and even Fanolint (though these events are only present near fans and do not extend indefinitely). The horizontal and vertical versions work differently, although both only affect you after the down-arc of your jump. Magnetic fields can have certain strengths defined in the event which affect the acceleration.

Horizontal

  • Moving against these slows you down to an hspeed of 2 pixels/f. Jump to avoid their influence in this case.
  • Moving along these speeds you up significantly. Hspeeds of up to 12 pixels/f have been observed. Jumping out of the field instantly returns you to 6 pixels/f.

Vertical

  • Moving horizontally within these can increase your hspeed beyond the normal 6 pixels/f limit.
  • Vertical movement behavior is uncertain, but the peak vspeed is thought to be based on your initial vspeed when leaving the ground (much like jumping from a spring into a vertical pipe).
  • There is a strange vertical ejection when leaving the magnetic field. Vspeed starts off at 13 pixels/f (up) and immediately starts decreasing. This makes more sense in Fanolint where the event can be exited from the top.
  • Holding down while on the ground keeps you there, although every few frames you leave the ground momentarily and are unable to jump.

Conveyers

While not moving on a conveyer, it will push Jazz at a speed of 2 pixels/f in one direction. Running with a conveyer will move Jazz along the normal acceleration curve but can push him beyond the normal cap of 6 pixels/f (probably up to 12, untested). The speed when running against a conveyer actually depends on Jazz's speed when landing on it. The speed will be unchanged upon landing with the acceleration being zero. The acceleration problem can be solved by being in the air during speed-increase frames.

Battleship skip

It is possible to shortcut the Battleship stages (episode 6, planet 3) by bringing a bird helper along to the stage, going to the outside of the ship where the end monitor is, and letting the bird clip into the wall as close to the monitor as possible. If the bird is close enough, it will spot the monitor and fire at it. Done properly, this can finish both stages within 25 seconds on the in-game timer.

It should be noted that while it's possible to get a bird in Battleship 1 with very little time loss to skip a massive amount of time in Battleship 2, in order to perform this in Battleship 1, one needs to get a bird from an alternate (slower) route in Crysilis 1 (extra time est. 15+ seconds) and not take any damage from then on, and the Battleship 1 skip saves much less time (est. 12-14 seconds). It is probably faster to skip doing the trick for Battleship 1.

Frame rules

What No speed bonus Speed bonus
Reverse 2 1
Release 4 4
Forward 8 2

The frame rule runs every non-lag frame and is reset on level entry.

Item/upgrade carryover

The following upgrades are carried over after finishing a stage:

The following upgrades are not carried over after finishing a stage:

Boss health

Base health can be found using a level editor such as J1E. Boss health is determined as following by each difficulty:

Episode Base Medium Turbo
Episode 1 25 45 65
Episode 2 60 80 100
Episode 3 40 60 80
Episode 4 20 40 60
Episode 5 45 65 85
Episode 6 80 100 120
Episode A 20 40 60
Episode B 24[1] 44 64
Episode C 20 40 60

[1] This boss's health is split over three parts.

Level editor

J1E is a useful tool for looking at level maps, object properties, and collision masks for tiles. Find it here and put it in the game's folder.

The level maps are organized as follows:

Filename Description
LEVEL0.000-017 Level 1 of the planets in episodes 1-6.
LEVEL1.000-017 Level 2 of the planets in episodes 1-6.
LEVEL0.018-023 Boss levels for episodes 1-6.
LEVEL0.030-038 Level 1 of the planets in episodes A-C.
LEVEL1.030-038 Level 2 of the planets in episodes A-C.
LEVEL0.039-041 Boss levels for episodes A-C.
LEVEL0.050-052 Levels for episode X.
LEVEL1.050 Secret level for episode X.
LEVEL2.* Secret levels for episodes 1-6 and A-C (some unused?)
LEVEL3.020 Gives an error in J1E. Can be opened in JCS94, but some events cause an exception. Appears to be an unused, incomplete Diamondus level.
LEVEL7.030 Unused, appears to be a copy of Diamondus 1 with the wrong tileset.

Planet names

Episode World Name
1 1 Diamondus
1 2 Tubelectric
1 3 Medivo
2 1 Letni
2 2 Technoir
2 3 Orbitus
3 1 Fanolint
3 2 Scraparap
3 3 Megairbase
4 1 Turtemple
4 2 Nippius
4 3 Jungrock
5 1 Marbelara
5 2 Sluggion
5 3 Dreempipes
6 1 Pezrock
6 2 Crysilis
6 3 Battleships
A 1 Exoticus
A 2 Industrius
A 3 Muckamok
B 1 Raneforus
B 2 Stonar
B 3 Deckstar
C 1 Ceramicus
C 2 Deserto
C 3 Lagunicus
<any> 4 Guardian

Version bugs and features:

1.0

  • Was distributed on floppies.
  • Only episodes 1-6.
  • Tubelectric 2 is short version.
  • Medivo 1 has proper ditch trigger.
  • Orbitus 2 is fairly easy.
  • Airboard ditching works.
  • Horizontal bounce beams can be passed through.
  • Recommended version for main episodes speedrun.

1.1

  • Was distributed on floppies.
  • Only episodes 1-6.
???

1.2

  • Was distributed on CD.
  • Episodes 1-6, A-C
  • Tubelectric 2 is long version (15-20 sec extra).
  • Medivo 1 ditch trigger is busted (costs few dozens of frames).
  • Orbitus 2 is fairly easy.
  • Airboard ditching works.
  • Horizontal bounce beams can be be passed through.
  • Recomended version for extra episodes speedrun (or main+extra).

1.3

  • Was distributed on CD.
  • Episodes 1-6, A-C, X(Holidaus)
  • Tubelectric 2 is short version (yes, even if 1.2 had long one)
  • Medivo 1 ditch trigger is there (but ditching does not work).
  • Orbitus 2 is almost impossible (but TAS strats still work).
  • Airboard ditching is busted (costs MASSIVE time).
  • Horizontal bounce beams can't be passed through (if not, would cost a lot of time)?


See also



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GameResources/DOS/JazzJackrabbit last edited by Mothrayas on 2017-08-03 18:27:38
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