What Duckfromportal said is right

. Just some additional information in case you (or others) don't know about the Timesplitters series at all:
Timesplitters is a First-Person shooter. Its weapons and maps are based on all sorts of time periods (e.g. Wild West, (Sovjet) Russia, Space Station etc). While it has a great story-mode, the thing that really characterizes Timesplitters it its multiplayer mode. It has a lot of maps, dozens of weapons and hundreds of playable characters like gingerbread-men, ducks, mad scientists and zombies.
Three games have been made so far (TimeSplitters, TimeSplitters 2 and TimeSplitters: Future Perfect). Unfortunately, a fourth Timesplitters was never made because the company ("Free Radical") that originally made the series, chose to develop another game before making a fourth TS (TS=TimeSplitters). Some concept art was made for TS4, but Free Radical went bankrupt before they had the chance of really creating TS4. The company was then bought out and renamed "Crytek UK"
It was still considered too much of a risk to make a game such as TimeSplitters, because it was unknown wether there was enough demand for such game. Fans made a petition in order to show them that enough people were interested in another TimeSplitters. Despite the efforts of the fans (100,000 strong for Timesplitters), no 4th game has been made.
Besides a new TS-game, fans also demanded a HD-Remake of the 3 previous Timesplitters-games. Crytek agreed and allowed a team of fans to develop a HD-Remake called "TIMESPLITTERS: REWIND". (Focusing on Multiplayer)
The devs are not allowed to make ANY money from this project. (Only donations to fund server costs are allowed) Therefore, Timesplitters will be fully free to play. Additionally, the devs are not allowed to use anything directly from the previous three games, so the project had to start from scratch and all characters(!), maps and weapons have to be recreated entirely. Therefore this task demands a lot of time, and given the fact that the developers are doing this in their spare time without being paid makes this project really admirable.
(Hangar) Hats off to the devs, their hard work is much appreciated
TL;DR: Timesplitters Rewind is a volunteer project that tries to remake the three previous (FPS) TimeSplitters games in HD, with all 287 unique original characters and without adding or changing too much in order to capture the spirit and true feeling of TimeSplitters. It will be fully free to play for PC (they have plans on releasing it to PS too). It will be sooo much fun!