I'm guessing a firm yes. I haven't purchased it, nor do I plan to, but the fact that the demo is in english, and that it isn't a heavily text/speech based game makes it almost certain to have english available. I think I mentioned somewhere before that the only 360 game I own that wasn't playable in english was Oblivion, and that's because of huge amount of recorded speech in the game.

I've also found that out of all of my games, Oblivion was the only one that had the text written on the disc itself in german. All the rest, even though I purchased them here, have english writing on the discs if I recall correctly.