- Executive Meddling: Electronic Arts wanted Future Perfect to feel like a more typical FPS, which is why that game is slower-paced and much lighter on its Goldeneye 1997 inspiration. On the other side of the coin, EA also mandated that the game place a stronger focus on its story. The resulting story and its humor has been praised as one of the game's biggest strengths.
- Orphaned Reference: The first level of Future Perfect has a Rewatch Bonus where you can see "The Hooded Man" (Cortez's future self in disguise) at a higher elevation at certain points. At the bridge section, a marine is seen calling him away from the turret he was using to shoot at the Splitter Mothership, but will be nowhere to be found once you get to this point in the actual "The Hooded Man" level. Some Dummied Out dialogue suggests that there would be marines helping Future Cortez in that mission ("Our hooded friend took out the Mothership! Incredible"), which also explains why Player 2's character is a generic marine when playing this level in Co-op.
- Sequel First: Japan received TimeSplitters 2 as the first game in the series, renamed TimeSplitter: Invaders of History.
- What Could Have Been:
- TimeSplitters 2:
- The Uzi was going to return in this game, and can be seen in an early trailer. However, it was replaced with the SBP90 later in development.
- A version of "Siberia" configured for Custom Arcade matches is Dummied Out within the game files. In the final game it is used for a few Challenges and Arcade League missions, but it cannot be played in multiplayer.
- Ramona Sosa was originally named Ramona Cortez. This, along with the fact that no previews ever mentioned Cortez and Hart by name suggests their names weren't decided until late in development.
- Sgt. Shivers is named Sgt. Shock on the website, who is a Palette Swap of him in the final game. This might actually be a case of the website's writer getting the two mixed up.
- Judging from the then-unnamed Hart's line of "When you select a time period you'll notice our appearance will change" on the game's website, she was intended to Body Surf alongside Cortez, who goes alone in the final game.
- Siberia has a GoldenEye-esque intro where the camera pans around the map before reaching the player and going into first person. The website shows the second level having a similar intro, implying that every level would start this way, and the data for some of these intros still exists in the game's files.
- The grenade launcher was usable in the Wild West level.
- The Reaper Splitter was originally named Berserker Splitter, which is kept in the German version and later used for its Suspiciously Similar Substitute in Future Perfect.
- Several of the Arcade League and Challenge missions were played in a different order (e.g. The "Classic" Challenges had "Hit Me Baby One Morgue Time" as the first mission rather than the last).
- Future Perfect:
- The most obvious example is the different uniform Cortez had, which is still visible on the back of the CD case.
- Anya and Amy Chen swapped voice actors partway through development.
- A leaked story outline reveals many differences in the plot. Most notable are Mary-Beth Casey being Cortez's partner in the mansion arc instead of Jo-Beth (who would have been a Damsel in Distress), Amy Chen dying at the end of the U-Genix arc, a Stinger revealing the Splitters weren't entirely erased, and the "Time-Loops" being an apparent late addition, as they aren't mentioned in the outline at all.
- Princess' health bar identified her by name the first time you fight her. In the final game she's just called "Creature".
- Edwina had a larger role being part of an objective where you would have to defeat a demon possessing her body (Ostensibly as Deadwina).
- The filename for the "VR" multiplayer map's default music is "ts3_rocket_launchsite_remaster44fx". This, coupled with the song's similarity to TS1's "Spaceways" theme, suggest that the song was originally intended as the BGM for a Spaceways map that was cut. "VR"'s original default BGM? The instrumental version of "Like a Robot", which has the filename "ts3_virtua44fx".
- TimeSplitters 4:
- TimeSplitters 2:
Trivia / TimeSplitters