My tastes really change over time. So, this is just what I feel right now, and it'll probably be different later:
2 Game isn't a roguelike. I used to be okay with experimental "roguelikes", but that was back when most roguelikes were traditional. Now adays there are so many games trying to jump on the "roguelike" bandwagon that have nothing to do with roguelikes, and it really, really bothers me. Sci fi is fine, but make sure it's a ROGUELIKE.
3 Too difficult. I want a game I can play, not a game that is going to make me pull my hair out in frustration. So many games treat ease of difficulty as a bug, and that's a HUGE mistake in my mind. Games should be playable.
3 Building from source. I'm just not going to, sorry. Nothing against your game, but give me binaries.
1 vi keys. They make me want to break my keyboard. I recommend wasd instead.
3 Ego. Some developers make it very clear that they think that their title is going to be the next minecraft, only better and more popular. It really bothers me. I don't mean advertising. I like advertising: it's clever and fun and we all have to do it, but nothing turns me off of a roguelike more than a developer with a massive ego about how important and successful and great their game is/will be.