I'm aiming for almost anything 2D. There isn't a forced perspective so you aren't stuck with top down. You could make an adventure game, a side scroller, a JRPG, or a simulation game. However there won't be support for procedural generated worlds or at least for now, so you can't make a game like Terraria or Starbound. There are a few other limitations but you have a nice variety of genres to choose from.