Genre: Rougelike-like (in space!)
Difficulty: 7 (keeping in mind that I've made it to the final boss three times, and never beaten him... on easy)
The rebels are winning the war, and you are the Federation's last chance. Armed with information, some weak weapons, and a skeleton crew, you must race to the Federation's headquarters to prevent final, crushing defeat. Along the way, you'll do things like route power between your ship's systems, make sure your spaceship is properly maintained, and ensure that everyone doesn't suffocate.
Also, you'll die. A lot.
FTL (redundantly named "FTL: Faster Than Light") ends up being a great deal more engrossing and addicting than its limited graphics (the game was one of the first completed games to be funded on Kickstarter) and severely complicated nature (play the turtorial first, seriously) might imply, the ship to ship combat is fun, with a great deal of depth. There end up being several different ways to skin just about every cat - you can board the other ship, you can light them on fire, you can cripple them, one system at a time, until they can do nothing but send you a desperate hail to cease fire (and then you can decide on whether or not you want to do just that). Events and encounters are all randomized based on sector. As a result, while you do end up seeing a lot of the same events after several playthroughs, you won't play the same game twice (and, in fact, depending on which ship you end up taking, your options and strategies may be completely different).
I picked up FTL during the Steam summer sale along with Hotline: Miami and Fez (both of those are also good games). I only did so because it was two dollars (seriously, the Steam summer sale is awesome - if you haven't checked it out before, do it next year), and because of the soundtrack (which is solid). It has ended up being the game I've played the most over the past few months by a long shot. If a rougelike-like in space sounds even remotely interesting, pick it up - you won't be sorry.
What's everyone else playing?