Eliminate Fast Ship Drift

The player's ship tends to drift towards the left and upward if you turn in that direction. It is an unfortunate bug in the game engine running on faster hardware that poses a disadvantage to any runner, where it is less of a concern on slower hardware. Crunching more frames means projectiles, including yours and enemies, are offset by a "grid" that roughly approximates that target of interest. The more frames the game renders, the faster the drift and more inaccurate projectiles are.

If you want to speedrun using my strategies, it can get fairly difficult to do since it requires approaching at precise angles to destroy everything in one go at a far distance away. Terminal Velocity's drift is much worse when played via virtual machines to the point of being literally unplayable! The only solution for Terminal Velocity is to slow down the emulator's processor speed like most DOS games suffer from their engines running too fast on a modern system.

You need to have Cheat Engine installed on your Windows computer for this task. Attach the Fury3 process into Cheat Engine first then toggle the speedhack on then toggle it off. This fast drifting is now eliminated to a much slower one the developers intended. This is because the game engine now refreshes at 60 frames per second as opposed to the real frame rate. Everything else such as controller input continues to operate at that original frame rate. You may not add other memory locations to aid your run as per the game rules!

Glitches and Bugs

Listed below are glitches and bugs of the Fury3 game engine I discovered. Some of these bugs aren't applicable to speedrunning but are very much undocumented. I'll briefly mention Terminal Velocity and Hellbender as they use similar game engines to Fury3's, but these games are beyond the scope of this guide.

# Perpetual Tunnel
## Terminal Velocity, Fury3
The game will permit you to enter it if you're less than forty-five degrees from its surface normal. On the contrary, you'll rebound and take damage as you would on any ground surface. This check is overlooked when you have invincibility or invisibility, granting access from any angle! If that tunnel is reversible after exiting, you're trapped unless either both of these timers tick to zero or by flying outside the tunnel activation points by hitting the walls upon leaving. This can be useful for entering mission-critical, one-way tunnels with bunkers containing either of these nearby. Terminal Velocity's invisibility does not function properly; it simply acts like invincibility without the enemies cease firing. Moreover, entering tunnels are restricted to those closer to flat ground. Tunnels on steep mountains will not register you as entering them and will smash your ship. Hellbender does not use the same tunnel format as Terminal Velocity's or Fury3's.

# Garbage Navigation
## Terminal Velocity, Fury3
When the last navigation point isn't a jump zone before the end of the mission, this is a classic example of undefined behavior in the programming community. In the best-case scenario, the mission ends without incident, witnessing your fighter aircraft flying away to space. Yet, there can be unrelated messages that may arise or different objectives on the head-up display. For example, some levels have a tunnel exit as the terminal navigation point. Completing that objective may show messages such as "Target Destroyed," "Mission Complete," or even "Mission Goal Ahead!". This bug is responsible for the crash at the end of New Kroy. There's a guide available on how to circumvent this crash. Hellbender enables you to switch objectives whenever you get stuck.

# Tunnel Skip 
## Terminal Velocity, Fury3
The navigation point system is flawed in that if entering tunnels is part of the mission, you can effectively skip every prior objective. Furthermore, if the guardian's location takes place inside the chamber, and you know where it is on the level, you can fly and enter the chamber exit tunnel and complete the mission! This bug is extremely useful for Any% with a catch: it only applies if that tunnel is part of the objective or is the first and sole objective; it doesn't apply if it isn't. Hellbender's tunnels are part of the terrain, and objectives cannot be skipped just by entering them.

# Chamber of Death
## Terminal Velocity, Fury3
You have invincibility frames persisting one second to prevent additional damage from enemy projectiles or flight recklessness; crashing into the ceiling while inside a chamber doesn't take into account those invincibility frames. As a result, ramming your fighter aircraft precisely towards the original and mirrored heightmap contact region will drain its shield every frame to the point of destroying it! Hellbender's fighter aircraft cannot be damaged by colliding with the surface, but it can from wall crushers in tunnels.

# Animation Multiplier
## Terminal Velocity, Fury3, Hellbender
Models with animated textures multiply their animations by the quantity that's visible onscreen. An obvious instance is powerups: when a powerup appears within sight, its animation speed runs as expected. Once a second, equal powerup appears, the rate will run twice as fast as it should. The model must be in the corresponding class to observe this behavior--a model that is a powerup won't speed up if that same model is an enemy!

# Infinite Ammunition
## Terminal Velocity, Fury3
The game's save file does not track the last non-Turbo weapon you used and can be abused to obtain infinite ammunition on disposable weapons such as missiles. You must not have that weapon beforehand! Pause the game while having Turbo as the current weapon and save. Fly towards an appropriate weapon powerup, grab that powerup, and select that weapon to save again but to a different file. Load that previous save file with Turbo present, and you should have zero ammunition on that weapon. Fire, and you achieved infinite ammunition! The glitch resolves when you pick up a powerup of that weapon. The FFF bomb is noticeable that you can only carry one at a time. Having infinite ammunition of these basically means you've won the game. Hellbender fixes this by having afterburners as a green bar next to the yellow hull and blue throttle bars respectively.

# Reverse Stereo
## Terminal Velocity, Fury3, Hellbender
The left and right channels of stereo and surround sounds are swapped in these games. Although it does not impact gameplay, Terminal Reality acknowledged this bug in the Terminal Velocity help manual but never managed to fix it.

# Ship Drift
## Terminal Velocity, Fury3, Hellbender
Ship drift is a feature in these games, but running on bleeding-edge hardware exposes this common bug among retro games: their engines running too fast. Fury3's engine is very adaptable, but there are a few spots where this consequence is unforeseen: fast ship drifting, spinning when taking damage, and projectiles out of line with your ship or enemy forces. See the following guide on how to eliminate ship drift for more explanation of this bug:
https://www.speedrun.com/fury3/guide/6itc9

# Camera Quirks
## Fury3
Moving the camera around using the Insert, Delete, +, and - keys in cockpit view has incomplete behavior when Terminal Velocity was ported from MS-DOS to Windows. Powerups don't face towards the camera like they always do. The view of the outside stays stationary when approaching the end of the tunnel.

New Kroy Crash Workaround

You may experience a crash at the end of New Kroy after you kill this planet's guardian, the City Generator. Unfortunately, a crash at some point means your run's dead, and you must restart the run. This guide will allow you to avoid this nasty crash and permit you to continue the run towards completion.

# Explanation
The game doesn't know what to do if the last navigation point isn't a jump zone. Instead, it tries to load whatever was formerly in memory then finish, which happens to correspond with Ares' second-and-final guardian, the Phase Shifter, and its music plays accordingly. If the City Generator's health points or HP happens to be zero, a crash will occur with a divide-by-zero exception. The guardian's enemy ID for both the Phase Shifter and the City Generator is zero, and thus it'll simply attempt to retrigger the same fight no matter what you do. However, if its HP is negative, the game survives and will allow you to run until the end.

Note: further analysis reveals the root case is not mainly with the guardian's zero HP crash, but rather how the game parses objective strings in the heads-up display or HUD. It doesn't reproduce when playing on Terminal Velocity or having the HUD hidden on Fury3.

# Approach
There's two guaranteed approaches to work around the crash. The City Generator has 200 HP, yet the game amplifies it 4096 times since that's the base strength of your weakest weapons: the ServoKientic and Rapid-Fire lasers. 

What you'll need is at least 13 ammunitions of Bion Fury Missiles as it deals 16x more damage to enemies than lasers. Mathematically, this is the ceiling of the number of hits required to defeat enemies: ceil(200/16)=13. You should never switch weapons because that increases your chances of a crash! By the time you destroy the City Generator, its HP will be negative (-32768, to be exact) and won't crash after exiting the tunnel. This recommended method works reliably and consistently.

If you do run out of Bion Fury Missiles, you must ram into the City Generator as that'll reduce its health by 1/8192 per second from it against your laser's 4096. The odds of a crash after ramming it are negligible, but a crash can still theoretically happen. There's approximately a 0.004% possibility on every ram, given you use weapons at random and have less than 13 Bion Fury Missiles left. The figure jumps to about 19% if you don't ram it.

Not all hope is lost in the instance you forget to ram the City Generator or not wanting to ram it after beating it. Your absolute last chance is to disable the head-up display or HUD by pressing the C key twice. This will show your aircraft's cockpit momentarily then nothing. Reenable the HUD by pressing C again on Sebek. This alternative strategy additionally prevents the game from crashing. So, you either overkill it with Bion Fury Missiles or let the game kill your run.

Tunnel Locations

If you want to speedrun under the All Tunnels category, I've compiled a list of where all of the tunnels are located on each mission by sector coordinates. The ones marked with => are one-way tunnels, and <=> are two-way tunnels. Tunnels before the one-way arrows are entrances, and tunnels after it are exits. Tunnels in bold are mission-required. You must enter two-way tunnels on both sides for 100% completion. It's displayed at the end-level statistics as a percentage of how many you've found.

# Terran
## Mission 1
41,12 => 46,44
42,61 <=> 46,225
## Mission 2
**151,83 => 133,95**
121,118 <=> 147,64
72,130 <=> 183,105
## Mission 3
94,79 <=> 160,99
**139,89 => 209,221**
**206,225 => 100,119**

# L24-D
## Mission 1
8,55 => 50,65
## Mission 2
**211,247 => 212,205**
**202,38 => 197,56**
## Mission 3
**104,96 => 58,88**

# Ares
## Mission 2
**242,63 => 120,126**
123,130 => 149,136
124,125 => 149,136
146,128 <=> 155,128
**150,128 => 187,129**
**187,129 => 226,105**
## Mission 3
**121,92 => 150,123**
**120,129 => 145,162**
**145,127 => 120,129**

# New Kroy
## Mission 1
86,57 => 149,178
152,181 => 87,56
## Mission 3
**187,72 => 125,125**
**123,130 => 137,172**

# Sebek
## Mission 1
173,160 => 148,141
156,180 => 223,205
## Mission 2
**138,140 => 108,123**
142,103 => 83,90
## Mission 3
**126,184 => 82,133**
**83,128 => 23,168**
122,224 => 77,223
19,196 <=> 110,8

# Vestra
## Mission 1
**34,215 => 41,207**
**100,199 => 101,205**
## Mission 2
**44,17 => 80,4**
**55,6 => 97,19**
55,33 => 119,127
124,131 => 58,34
## Mission 3
**98,32 => 111,21**
**133,23 => 130,39**
**102,14 => 120,132**
**123,132 => 118,63**

# Tiamat
## Mission 1
11,29 => 39,33
12,48 => 67,52
## Mission 2
63,220 => 126,130
126,122 => 73,207
## Mission 3
**193,195 => 129,131**
**128,132 => 143,170**

# Fury
## Mission 2
76,191 => 128,190
151,128 => 81,190
123,191 => 156,127
**190,152 => 191,110**
190,115 => 191,147
## Mission 3
**43,87 => 156,225**
**156,230 => 52,103**
53,87 => 43,104
34,45 => 47,137
46,133 => 43,45

名称	作者
Eliminate Fast Ship Drift	MightyTTC 3 years ago
Glitches and Bugs	MightyTTC 3 years ago
New Kroy Crash Workaround	MightyTTC 3 years ago
Tunnel Locations	MightyTTC 4 years ago