Pro tip: if you're going to announce a game, don't do this.
The good news is that if you were a fan of TimeSplitters, you'll be getting a fanmade remake in 2018. The bad news is we have no idea what the game actually looks like, because the "teaser" is little more than somebody messing around with 3D animation for the first time.
I'm not even joking. It's a series of green shards, rotating slowly with some nondescript music in the background before the TimeSplitters Rewind logo appears like it's something out of Harry Potter.
If you're still confused, TimeSplitters Rewind is trying to recreate the multiplayer portion of TimeSplitters 2, an arena shooter from Free Radical Design that shipped on the Xbox, PS2 and GameCube. It was famous back in the day because it shipped with a map creator, 16 game modes, support for 10 AI bots, an arcade league and more.
But as I noted with the beta of DOOM's multiplayer last year, arena shooters have a steep hill to climb. They're not popular anymore, even on their home platform of the PC. But an awful lot can change in a year: just look at 2016.
IF you want to catch up on all the particulars of TimeSplitters Rewind, you can do so here. The official site's certainly more exhaustive than the trailer, even though it hasn't been updated in several months.