The flow of time

Tutorial space

The tutorial space is missing entirely from Dec 1. Unfinished versions of it appear in both FSS25 and Taikenban. A mostly-finished version appears in Jan 3.

The main difference between the two unfinished versions is the survivor at the end: it's Danny Ortiz in FSS25 and Richard Wells in Taikenban.

One noticeable difference between the later versions is also the survivor at the end. It's a featureless dummy in Jan 3 and a more realistic one in Final. In addition, Final has a training sequence for the "press down to jump away from a backdraft" move.

Mission 1

Mission 1 is close to complete in all of the prereleases. There are various differences across builds in survivor and object placement, but they're pretty minor. There are a few differences in the map that are unique to Dec 1. The boss encounter is similar in all builds.

One noticeable map difference: there is a room off the Lv. 08 North Transit hallway in the Dec 1 build that's not there in later builds. Also, the big room with the reactor in its center (Maztabaluxor Lv. 8) is different in Dec 1; you don't enter it at the ground level.

Dec 1 also has red arrows and signs on floors and walls that point you in the right direction. These are (mostly) gone in later builds — presumably because you're meant to rely on voice navigation data.

Dec 1 has a little trap in Supply Room 03rd that isn't there in other versions. Once you're in it, a shutter behind the entrance closes. You have to jump up through a hole in the floor and go around to the door on the upper level. FSS25 has something else that's unique in the same place: inside the room is a robot and some fuel canisters. When you approach the fuel canisters, they explode, taking the robot down in the process (video).

Dec 1 and FSS25 have yellow fuel canisters in Workshop D103-08 A. These act like the  blue ones, and are replaced with blue ones in later builds. Their object data remains on the final disc, but they're not used anywhere.

Dec 1 has a "burning sun" enemy on the Lv. 99 South Transit path (just after you turn on the lights for a second time). That remains in FSS25 and Taikenban, but is gone in Jan 3 and Final. These enemies appear in different parts of Mission 1 when you're doing replays, but they're never on the main path.

Mission 2

Mission 2 seems to have taken the longest to finish. The last section in particular is notably empty in every build before the final one.

The intro sequence differs in builds that have broken swimming. In FSS25 and Taikenban, Shou or Tillis sprint through the submerged tunnel. In the other  versions they swim properly.

Object and obstacle placement varies among versions. For example, the hallway after the Dolphin Tank has pink flames in some prerelease versions, pink flames and a robot in others, and orange flames with no robot in Final.

The dolphin interactions are hit or miss in the prototypes. They more or less work in Dec 1 and Jan 3. In FSS25 the Dolphin will fling you into a wall and prevent you from continuing (video). In Taikenban, the dolphin won't carry you out of its tank, which prevents you from continuing. 

Dec 1 has an entire section that's missing in later builds. After the dolphin tank is a fairly difficult maze of corridors on two levels. You need to find a switch to open a shutter to continue. There is a survivor hidden in one of the remote rooms.

There's another, less complicated, maze of hallways with red doors in Dec 1. Rolling fuel canisters are added to it in FSS25. The canisters are gone in Taikenban (they've moved to a different hallway), but are back in Jan 3. Both the red doors and the canisters are gone in the final.

In Dec 1, you encounter a very glitchy survivor that seems to be re-enacting the Peter Smith scene from Mission 1 (he's the one banging on the elevator door at the end of the first round). A similarly glitchy person is standing in the area labeled Grampus Path. The first person is gone in later builds, but the second is replaced by Leonard Kennedy in FSS25 and Taikenban. They're both gone by Jan 3.

There are some limited changes to the map across versions. After you swim through the tunnels with the dolphin, the prerelease versions put you in a room with two vents. The final version replaces the vents with an open shutter.

None of the prereleases have the animation that plays during the cut scene in the monitor room. Final shows a rotating wireframe model of Ocean Park during the dialog.

The boss encounter is unfinished in the prereleases. You can't access the boss area from the last room in Dec 1 or Taikenban, and you can't even get to the last room in FSS25. Final has a scripted segment at the beginning of the boss round, but that isn't implemented in the earlier builds — you can control your character on the way down to the boss's area.

The cutscene in which Shou or Tillis rejoin the other rangers after riding on the dolphin seems to have been a late addition; it's not there until Final.

Mission 3

Most of Mission 3 is nailed down as of Dec 1, but the Neal rescue sequence is missing until Final. There are a few minor object placement variations across builds.

Dec 1 and FSS25 are missing the elevator in Spring Valley Square. It's actually there, but you can't see it. Both of those have unfinished textures for the floors in the second round. There's a safety gate on the upper level of Frozen Bell Square in the prereleases, but it's gone in Final.

The bee enemies are green instead of yellow in the prereleases. They take more hits to defeat, as does the drill robot.

Dec 1, FSS25, and Taikenban have objects floating around in the second round. If you touch or shoot at them, they bounce around the room (video). This was presumably some sort of demonstration of the weak gravity on the space station, but it's in the part of that round where you can walk normally.

Stick Canyon Path is really interesting the prerelease builds. Behind each of the four doors is a different little challenge that gives you access to a switch. One room has an anti-gravity section and another lets you ride upward on the air current produced by a spinning fan (there are more details the Jan 3 article). These features definitely aren't there in Final.

The scene with Big and the deconstruction crew's foreman evolves over time. In Dec 1, neither big nor the foreman are there — a little girl appears instead. In the later builds they both show up, but the foreman has a different model and more primitive animations.

Dec 1 has the same little girl standing in the middle of Stick Canyon Path. She's replaced by a levitating Neal in FSS25 and Taikenban. Levitating Neal has moved into the next room as of Jan 3. His cutscene isn't implemented until Final.

The boss's difficult is dialed up in all the prerelease versions: you have to knock off all its armor before you can deal any damage.

Mission 4

Mission 4 is present in Dec 1, but the last round crashes right after you enter it. It's playable in the rest of prerelease builds, but none of them have fully functional boss fights — only Jan 3 even allows access to the final boss round.

The opening section is really difficult in Dec 1! The spotlight enemies are constantly bombarding you with flames, and there are pairs of "burning sun" enemies blocking your path at multiple points. The difficulty is dialed down a bit in FSS25 and Taikenban , but the same enemies are present. The extra enemies are gone in Jan 3. The prerelease builds are missing the switch that lets you into the ice room; instead there's a mostly-invisible block that you can ride up to its entrance.

The prerelease versions of the water section are more or less the same as in Final. All the prerelease versions are tedious because of the unfinished swimming controls. You can't use the elevator to finish this section in FSS25 or Taikenban, so you have to skip ahead.

Dec 1 has different visuals in the background in the third section — it's the same image, but the positioning is wrong. FSS25 and Taikenban are interesting; they've got the Burning Ship docked next to the platform (video). The spotlight enemies are hanging around, too. Once you get to the top, all the prerelease versions have a broken version of the floating crystal boss — it doesn't fight back at all.

None of the prerelease versions have you play the Burning Ship sub-game before proceeding. A very unfinished version of it is present in Jan 3 (here is a video).

The fourth section is unusable in Dec 1 due to some broken object code, but it can be explored with hacking. The cyclops monster that protects Iria's room is missing in the prerelease versions, but Dec 1 and FSS25 have a pair of "burning sun" enemies there instead (video). Iria's hypersleep unit is present in Dec 1 and FSS25, but it's gone in Taikenban and Jan 3. The cutscene with the other Rangers doesn't appear until Final.

FSS25 and Jan 3 let you proceed past Iria's room into a chamber with a strange fuel canister elevator. Jan 3 has a partial version of the final boss. Its globe form plays about the same, but its last form is missing all but one of its attack types. In FSS25, the attacks are fatal even if you possess crystals.

General differences

• Crystal limits: the prereleases cap you at 99. Final doesn't have any practical limit.

• Crystal visuals: the prereleases use more saturated colors for crystals before they're collected. The crystal shatter effect isn't implemented till Final.

• Survivors: the prerelease builds give survivors different names (details), models, and animations.

• Title cards: none of the prereleases show the mission names in the opening sequences.

• Generate: none of the prereleases give you access to the alternate versions of the missions on replay.

• Burning Ship sub-game: a very preliminary version is present in Jan 3; it's missing in the other prereleases.

• Voice navigation: before Final, it really only works in Jan 3.

• Limit: Neither switches nor survivors decrease it in Dec 1; they work properly starting with FSS25.

• Timer:

  • Dec 1 and Final: The timer starts from 0 and counts up

  • FSS25, Taikenban, Jan 3: The timer starts from 10 minutes and counts down

• Rescues: You need to bank at least 5 crystals to rescue someone; 10 to also get a continue.

  • Dec 1: If you have more than 10 crystals, they'll all be banked, leaving you with 0.

  • FSS25: If you have more than 10 crystals, they'll all be banked, but you'll only lose 10.

  • Later builds: Behavior matches the final release.

• Swimming:

  • Prereleases: You can't jet upward; you have to float. You can fire underwater.

  • FSS25 and Taikenban: Swimming is broken; you can run along the bottom of submerged areas.

• Mail:

  • Dec 1: There are a small number of mails written

  • FSS25 and Taikenban: There's no way to access the Mail or Rescue List screens, but the discs have the same mail items as Dec 1.

  • Jan 3: The Mail screen is the same as the Rescue List, but the disc is missing the mail data.

• Multiplayer:

  • Dec 1: Cooperative multiplayer can be enabled from the hidden debug menu.

  • FSS25 and Taikenban: The second player option is removed from the debug screen.

  • Jan 3: VS MODE can be selected from the Mode screen. Skipping out of the arena allows for something like cooperative multiplayer. 

  • Final: The only traces of multiplayer modes available without hacking are in the sound test.

• Loading screens:

  • Tillis: Dec 1 has a unique loading screen; it's changed by FSS25.

  • Chris: Dec 1 has a loading screen for her; it's removed entirely in the other builds. Shou's is used in the final.