About Editing This Page

Game Info

• Official site - Download game for free, manual, hint book.
  • Only use this freeware version from Adept Software (Adam Pederson) v1.5 - jetpak15.zip.
• Discussion thread
• Level pack to play with in level editor.
  • Using this pack, you can jump directly to any level, view false blocks, play it, or even edit it.
• Game speed is not emulated properly in JPC-RR at current. All speeds are speed 8.
• Stunner or Shield items and other random drops are not used (or using them counts as a different category).
  • Nach: Really? Who decided this?
    • Svimmer: Slamo tried manipulating the drops, but didn't find a real way (it's on the second page of the thread). The possible logic behind not using them at all is a) it's too haphazard if they can't be properly manipulated, b) it would give the run a cheeky feel, like in some levels you're "supposed" to have no fuel. Also if it was found out how to manipulate them later, it would leave more space for that category if they weren't used here at all.

Debugging Codes

• Extra Life: TAB + 2 + L
• Fuel Refill: TAB + 2 + F
• Invincibility: TAB + 2 + I For the entire duration of the current level.
• Skip Level: TAB + 2 + S

JPC-RR Image

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Naming Conventions (Svimmer)

• • I added my name next to the section title to become the "caretaker" for this section. I added a discussion about this in the discussions section of this page.

• the [G]RP - This (Game Resources) page.
• the Discussion Thread - linked under "Game Info"

• Enemies - also "monsters" (see Enemies section)

• Y-,P- and G-Teleporter - Yellow, Purple and Green teleporters.
• R-,B- and G-Barrier - the red, blue and green "force fields"
• R-,B- and G-Button/Switch - the ones that [de]activate barriers. The switches are "Floor Switches" in the documentation.

• black/space

• door

• phasing - phasing out blocks
• phase in/phase out - what blocks do when phased
• thrusting - or simply flying, using the jetpack
• running/walking - these are both ok
• trapping - you can trap enemies inside phasing-in blocks

• gem - the green things you're collecting
• tank/d-tank - fuel tank or double fuel tank
• shield - the "invulnerability" power-up
• stunner - freezes enemies

• block - sometimes called "tiles", but this seems more common in discussion, means something else in the editor
• pink, lred, dred, crate - the four types of phasable blocks

• ladder/uladder/dladder/aladder - that is "up ladder" and "down ladder" or more generally "autoladder"
  • Svim: manual just has "moving ladders" but u-ladder or d-ladder is more accurate
• [l-/r-]conveyor - [left-right] conveyor belts, or "moving platforms"
• charger/drain - the tiles that replenish/drain fuel
• spear - the hidden trap that shoots up from the ground
• spikes - the visible type of deadly trap, not to be confused with the Spinner, one of the enemies

• moss/ice - manual "sludgy bricks"/"icy bricks"

• sp/f - subpixels per frame.
• sp/f^2 - subpixels per frame squared.
• hspeed - Horizontal speed.
• vspeed - Vertical speed.

Open Game-Related Questions

• Speed when rapidly climbing a ladder/autoladder by constantly jumping?

• Also someone mentioned you walk faster when out of fuel? At what speed then?
  • Nach: I don't know about walking, but jumping is certainly faster without fuel.
  • Svim: If it's been measured that there's no difference, could someone remove this question?

• Can enemy movement patterns be manipulated other than by one's own positioning, i.e. through the RNG? How do trackbots "track" you exactly, what rules do they follow?

Game Data

Measurements

• 26 blocks wide.
• 16 blocks high.
• 1 block is 24 pixels.
• 1 pixel is 16 subpixels.
• Height of Jump is 565 subpixels.
• Distance of Jump is 1117 subpixels.

Speeds

• Jetpack up terminal speed: 64 sp/f.
• Fall down terminal vspeed: 64 sp/f.
• Fall down terminal hspeed: 20 sp/f.
• Jetpack terminal hspeed: 64 sp/f.
• Walking speed: 55 sp/f.
• Walking speed with conveyor: 60 sp/f.
• Walking speed against conveyor: 25 sp/f.
• Walking on moss: 32 sp/f.
• Jump initial speed up: 68 sp/f.
• Jump initial hspeed: 62 sp/f.
• Climbing ladders: 45 sp/f (normal)
• Climbing ladders: 20 sp/f (against)
• Climbing ladders: 64 sp/f (with motion)

Acceleration:

• Jump horizontal deceleration: 2 sp/f^2
• In-air horizontal acceleration: 3 sp/f^2 (hspeed >20 sp/f, can undershoot)
• In-air horizontal acceleration: 5 sp/f^2 (hspeed <=20 sp/f).
• Acceleration of gravity: 5 sp/f^2 (jumping)
• Acceleration of gravity: 6 sp/f^2 (jetpack cutoff)
• Jetpack vertical acceleration: 4 sp/f^2.
• Jetpack horizontal acceleration: 6 sp/f^2.

Border cases:

• 1st frame of running jump: 55,-68 sp/f (yes, 55, not existing hspeed).
• 2nd frame of running jump: 62,-68 sp/f
• 1st frame of jetpacking adds hspeed iff already moving horizontally.
• 1st frame of cliff runoff: 5,-64 sp/f (if holding jump, normal jump acceleration on this frame).

Phasing

• Phasing a pink block:
• Phasing a light red brick: 26 frames.
• Phasing a dark red brick: 56 frames.
• Return of a pink block:
• Return of a light red brick: 94 frames.
• Return of a dark red brick: 226 frames.

• Teleporting: 20 frames.

Fuel

• Full tank: 10000 units.
• Half tank: 5000 units.
• Fuel usage: 10 units/frame.
• Charger recharge rate: 10 units/frame.
• Fuel drain drain rate: 20 units/frame.

Randomness

uint32_t seed; //Seed is 32 bits
int rand()
{
  seed = seed*22695477 + 1; //Seed multiplies and adds, and possibly overflows
  return (seed >> 16) & 32767; //Use bits 16-30 for requested random value
}

• Svim: what does this mean in plain language? it uses the RNG, but doesn't change it?
  • Ilari: The random number sequence doesn't change, but the position of future random throws, and thus the random throws themselves, changes.
  • Ilari: This can be used for luck manipulation. Due to rarity of bonus items, it is difficult to manipulate those. However, manipulating random enemy AIs should be much more feasible.

Enemies

• Any enemy affected by gravity (Trackbots and Steel Balls) has a falling speed of 64 sp/f with no acceleration (speed is achieved immediately).

	Name	Speed	Behavior
	Trackbot	Horizontal: 43 sp/f, Vertical (ladder): 33 sp/f	Affected by gravity. Generally heads in your direction. Makes random decisions at ladder/floor intersections - these can be manipulated through phaser usage, although some decisions cannot be changed.
	Steel Ball / Marble	Horizontal: 59 sp/f	Affected by gravity. Reverses horizontal direction when it hits a wall.
	Spring	Vertical: 50 sp/f	Reverses vertical direction when it hits a surface. Takes 5 frames to reverse direction.
	Missile	Horizontal and vertical: 64 sp/f	Does a 90 degree clockwise turn when it hits a wall.
	Spikes / Spinner	Horizontal and vertical: 20 sp/f	Moves diagonally at all times. Bounces at a 90 degree angle when it hits a surface, and will reverse direction completely if it hits a corner perfectly.
	Flitzer	Horizontal and vertical: 11 sp/f	Randomly moves in one of eight directions. Changes direction when it hits a wall, otherwise changes direction every 7 frames.
	Batbot	Horizontal: 10 sp/f, Vertical: 17 sp/f	Will head in your direction once it hits a surface, the movement is not random. Capable of moving diagonally.
	Homer	Horizontal and vertical: 4 sp/f	Moves diagonally until it matches your x or y coordinate, then travels in a straight line at you. Can move through all blocks.

Known tricks

Movement

• You can jump off an empty block if you started the level above it.
• You can hold down or phase horizontally while flying to keep your height.
• Phasing up/down shifts your position to directly adjacent to the block. Even in mid-air it aligns you to the grid.
• Phasing up/down stops your movement even when mid-air.
• Pressing up/down while attached to ladders also causes you to align to the grid.

Extreme Jumps

• with no free space above
  • onto a ladder
  • onto a platform

• with one block of free space above
  • onto a ladder
    • 3,1 (quite precise)
    • 4,-1
  • onto a platform

• with two or more blocks of free space above
  • onto a ladder
  • onto a platform
    • 4,0

Enemies

• Enemies always teleport when hitting a TP.
• Enemies trapped in blocks cannot hurt you unless released.
• Sometimes certain enemies move faster than others of their kind.
  • Applies at least to: Marbles, Springs?
    • Nach: Some Marbles change speed over time, not entire sure why.
    • Henke37: Could be inconsistent game load? I recall the game getting slower when there are more enemies in the level.
  • Svim: May have something to do with their spawn square. (unconfirmed)

Miscellaneous

• You can just phase a lred block horizontally that you have to jump to reach.
• After dying you can still finish the level by landing at/lifting to the door.
• You are invulnerable during teleportation. This cannot be repeated, there is a period of vulnerability in between two teleports even when holding down. Items may be collected during teleporting and buttons and switches are also operable.
• Teleporters may teleport to the wrong color if the level has too many of them. Unfortunately, there doesn't seem to be enough teleporters in any of the levels for this to happen.

Level Strategies

ToDo

• Levels
  • Describe what is important in each level
  • Different route strategies. Add .png's (and videos?) for each.
• Enemies
  • Fill in missing data.
  • Move enemy images to TASVideos server.
• Adding more information about running the game in JPC-RR. Possibly even the hd image itself, what DOS was used (where it's found), a link to a subpage containing all the WIP's and possible lua scripts, memory locations etc.
• Filling out the jumping table.

Discussion About This Page