TASVideos

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

Submission #6556: willbobsled's PSX X-COM: UFO Defense in 14:44.04

Console: Sony PlayStation
Game name: X-COM: UFO Defense
Game version: USA
ROM filename: X-Com - UFO Defense (USA).cue
Branch:
Emulator: BizHawk 2.3.2
Movie length: 14:44.04
FrameCount: 52417
Re-record count: 21347
Author's real name: Will Becker
Author's nickname: willbobsled
Submitter: willbobsled
Submitted at: 2019-12-02 11:42:48
Text last edited at: 2020-05-07 10:16:15
Text last edited by: Spikestuff
Download: Download (14089 bytes)
Status: published
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Author's comments and explanations:
In the distant future of 1999, the human race is facing a great threat to its survival. Reports of violent human abductions and horrific experimentation have created a world-wide atmosphere of fear. Mass public hysteria has only served to expose Earth's impotence against a vastly superior technology. The decision was made to establish a covert independent body to combat, investigate and defeat the alien threat.

Game objectives

  • Emulator used: BizHawk 2.3.2
  • Takes damage to save time
  • Abuses programming errors
  • Heavy luck manipulation
  • Uses hardest difficulty
  • Genre: Strategy


Please turn on Subtitles/CC for basic explanation of route and techniques.


(Link to video)

About goal choice

X-COM UFO Defense was released on multiple platforms upon its initial release, including: DOS, PSX, Amiga and CD32. An open-source clone of the game titled OpenXcom commenced in 2010 and continues to be maintained by volunteers. Although the modernised GUI allows for fastest completion time, the lack of a finished release version was a strong deterrent when other ports were readily available. The Amiga and CD32 ports are clearly the worst options as they suffer from abysmal loading times while adding nothing to gameplay.

DOS and PSX each provide some good arguments to be considered the preferred TAS platform. Unfortunately the initial DOS release suffers from a bug that reverts the game difficulty to Beginner after the first Battlescape mission, which would result in less interesting gameplay and violate the guideline of playing on the hardest difficulty. Although this was fixed in rereleases and despite the DOS version playing much faster than its counterpart, I decided to use the PSX port as fewer arbitrary restrictions were required to set a standard for emulation. Furthermore, the PSX port introduced new glitches that enhance viewability, uses updated music and graphics, and also includes exclusive cutscenes which sets a more defined goal for completion.

Although the PSX port was compatible with the PlayStation Mouse, I placed an additional restriction on myself to exclusively use the standard gamepad for all game input. This was done primarily because BizHawk does not officially provide mouse-support, but also because there would not be a substantial difference in the time required to beat the game due to optimised navigation.

The game difficulty has been set to Superhuman, which is the hardest of the five available difficulty settings. Easier difficulty settings would allow the game to be completed slightly quicker due to less time spent on alien movements but was ignored in order to conform to tasvideos guidelines on playing the most difficult setting, especially for a strategy game. Incidentally, Beginner would require the most time of all, as the designated 'special' spawn locations reserved for higher ranked aliens would require both Floater Leaders to spawn in an inconvenient location.


Techniques and glitches

  • Most RNG rolls between 50%-150% of a given value, such as research times and explosions.
  • Conventional weapons deal bonus stun damage to their targets, between 0%-25% of the damage dealt after armour has been applied. This exploit is necessary to quickly capture aliens for interrogation and has been heavily abused in order to forego the time required to research and equip specialised stun weapons.
  • Intercept cancels allow us to reroll the seed depending on the calendar date. This is used to manipulate Battlescape setups, research times, and alien mission sequences.
  • Second chance research grants a second RNG roll by pressing Start immediately after beginning a new research project, which saves the need for using excess Intercept cancels.
  • Research Rollover bug allows for Scientists to be allocated to multiple research projects.
  • February Terror manipulation allows us to maintain a satisfactory monthly rating by the funding council. The greatest danger for the player is to fail to achieve the minimum score for two consecutive months, but this can be avoided by deferring the most significant alien scoring mission until March with Intercept cancels.
  • Offscreen movement prevents the display of time-consuming animations and allows for much quicker movement on the Battlescape.
  • Screen scrolling during the Battlescape will reroll the trajectory and damage of X-COM weapons.
  • Input interrupt glitch is triggered by an alien performing an action on a certain frame which is then interrupted by the player pressing L1 or R1. This causes a wide variety of unintended results including soft-locks, zombie states, and bizarre trajectories. The latter is used twice in Battlescape II.

Stage by stage comments

Geoscape I

A new game commences and the hardest difficulty is selected. The X-COM base is built near the South Pole, and time passes until the Sectoid Medium Scout lands in the vicinity. We Intercept cancel once to manipulate a more desirable board and send the Skyranger to retrieve the required UFO components.

Battlescape I

We equip a pistol to Gallagher's left hand during the loadout phase to lessen the need for Screen scrolling, and also a grenade to Gorokhova in order to later take damage to save time. After the first two Sectoids are killed, the options menu is quickly accessed to change movement speeds to maximum before deploying Jones with Offscreen movement before ending the turn. Once we regain control, Jones is sent to locate the Sectoid in the distance to grant LOF to Gallagher, then Jones enters the UFO with mutual surprise and kills two Sectoids with an Auto Shot, before the remaining aliens are picked off. Before the mission ends, Gorokhova primes a grenade and kills himself along with four others to save the time needed to sack them.

Geoscape II

The Interceptors are not needed and are sacked to lower maintenance costs, and the radar is dismantled to prevent detected UFOs from prompting for unnecessary X-COM response. Next the empty space in the Living Quarters is filled with Scientists to speed up research. Finally, the remaining facilities are built: an Alien Containment to house captured aliens, a Living Quarters for more Scientists and Engineers, and a Workshop for more workspace to increase space requirements. When the Scientists arrive after a few days, research projects are started in a certain order to roll for smaller values, and are allocated to the relevant UFO components. We then Intercept cancel once to manipulate a Floater base to be built in late February, and continue using the Research rollover bug while ignoring all other prompts.

Once February begins, we hire the remaining staff and Intercept cancel twice to delay the February Terror sequence. We now use Second chance research for UFO Construction and again later for New Fighter-Transporter. After three Intercept cancels before New Fighter Craft and two more after, we manufacture all the remaining materials needed to build the Avenger, followed by an Intercept cancel both before and after Ultimate Craft. Finally, we Intercept cancel once before the end of the month and four times after and then wait until 3rd March to manipulate a desirable Floater base board.

Battlescape II

During the loadout phase we equip Petrov with a Heavy Cannon with High Explosive rounds and abandon all grenades and spare clips to avoid being overencumbered when carrying the collected loot. Our first movement will trigger the Floater Commander's reaction fire, and the second shot would kill Petrov if not for the Input interrupt glitch which deflects the shot into the floor. Petrov gets to work, knocking the Commander unconscious with bonus stun and killing a Reaper. On Turn-2 Petrov knocks out a Soldier and kills another Reaper, while Gallagher and Jones Offscreen movement into position to manipulate the Floater Leader to come downstairs. On Turn-3 Jones opens the door and collects the Leader after Petrov knocks it out, as well as a Blaster Launcher and Blaster Bomb, while Gallagher collects the unconscious Soldier and prepares to evacuate. The Floaters have now had time to deploy their forces and would overwhelm the intruders if not for a final display of valour as Petrov selflessly dives in front of Jones to lure the Reaper's melee attack.

The Reaper takes the bait, lunging at Petrov, killing her instantly with a single bite. However, her sacrifice is not in vain, as the corridor is now swarming with aggravated aliens whose volleys of plasma are obstructed by the cumbersome Reaper. Finally a Floater launches a Stun Bomb directly at Jones but an Input interrupt glitch causes a premature explosion that incapacitates the garrison. Gallagher captures the unconscious Commander and the two remaining X-COM soldiers escape.

Geoscape III

After two Intercept cancels, research recommences in preparation for the final phase of the game. Second chance research is used for Blaster Launcher, Blaster Bomb and Floater Soldier, and production begins on the Avenger which will send us to Cydonia. Another Intercept cancel on 13th March and Second chance research for Alien Origins, followed by yet another Intercept cancel on 18th March lands us on a seed that will allow us to leave the planet by early April. Finally we use Second chance research for The Martian Solution and Floater Commander, and prepare the completed Avenger. We wait until after noon on 7th April and following one final Intercept cancel we send the Ultimate Craft to its final destination.

Mars: Cydonia Landing

This mission is fairly self-explanatory. We give Gallagher the loaded Blaster Launcher during loadout and send him to the green lift tiles that allow us to enter the final mission in a single turn, using Offscreen movement to save time.

Mars: The Final Assault

We finally get to witness the destructive power of the fearsome Blaster Launcher. The guided missile follows selected waypoints to weave a path through the labyrinth and collides into the ceiling beneath the Alien Brain, destroying it from a distance. Once we end the turn, the final cutscene plays and the game is complete.

Other comments

Below is a table that shows the initial research times before Research Rollover for all projects used in the TAS:
Project 0x Avg Init 2nd
Alien Alloys 01215E 400 240
Elerium-115 01214A 450 260
UFO Power Source 01214E 450 251
UFO Navigation 012150 450 257
UFO Construction 012152 450 242
New Fighter Craft 012160 600 340
New Fighter-Transporter 012162 700 360
Ultimate Craft 012164 900 462
Blaster Launcher 012140 900 471
Blaster Bomb 012142 300 193
Floater Soldier 0121E2 192 114
Alien Origins 01219C 300 192
Floater Leader 0121DA 192 102
The Martian Solution 01219E 500 270
Floater Commander 0121D8 192 101
Cydonia or Bust 0121A0 600 335

It is possible that there is a marginally faster route by provoking the Aliens into retaliating against the X-COM base, which is always led by a Commander, although the only way to achieve victory in these missions is to kill or incapacitate all invading aliens, but this may not be any faster. It is also theoretically possible to capture the aliens needed for interrogation in fewer than four turns, but it should be noted that the board used in this TAS is much faster than any alternative I was able to find. Without sequence breaks, I don't believe that the PSX port can be significantly improved.


Memory: Claiming for judging.

Memory: All right so when I first saw an X-COM TAS pop up I thought it was gonna be kinda lame since I knew you didn't have to do many missions to get to Cydonia, but in fact it actually ruled. I loved the glitch that basically allows you to rotate enemy bullets. Audience enjoyed it as well.

Accepting to Moons.

Spikestuff: Publishing.

Spikestuff: If anyone wants to dump this in the future use 2.2.2 as 2.3 to 2.4 can crash when dumping.


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