From The TimeSplitters Wiki

Timesplitters is the first game in the Timesplitters trilogy. It contains the mapmaker, 9 story missions, with a male and female playable character in each, 4-player arcade, over 50 characters and an unlockable challenge mode that is really challenging.

Contents 1 Story mode 2 Arcade mode 2.1 Modes 3 Challenge mode

Story mode

The story mode is a bunch of missions, each of them are simple: find the thing and bring it somewhere(Usually the start point.). Each mission has six unlockables: One for completing the stage on easy,One for completing the stage on normal, and one for completing the stage on hard, as well as one that requires to beat the stage fast enough(Once again, one per difficulty.).

Arcade mode

Arcade mode features yourself trying to beat your enemies. You can have up to 4 human-controlled characters and 10 bots. You unlock nothing, but things unlocked are for this mode.

Modes

Deathmatch

Capture the bag

Bagtag

Escort(Not always available)

Last stand(Not always available)

Challenge mode

You unlock challenge mode after beating the 1920 spaceways level. It has many missions with an high difficulty level. They range from fighting timesplitters on a spaceship to fighing for a bag of bones in a graveyard. Each mission unlocks things in this order: X-A=Character, X-B=cheat, X-C=character.