A great game mechanic that is dragged down by excessive difficulty and randomly impossible encounters.
Battles can be fun, and tense, affairs trying to decide which components to repair first, and how to fight the inevitable fires that break out. Do you risk your crew? Do you open the doors to vacuum to starve the fire? It becomes even more complicated when you have boarders to contend with at the same time.
However, despite all FTL has going for it, its excessive difficulty can be extremely frustrating given the designers effectively remove the ability to save games (you can sort of save, but its only for continuing where you left off. You can never load after a failed encounter.) With this, every time you die, you start from the beginning. On the one hand, its a short trip that takes about an hour or so to get the final encounter, on the other, making it anywhere near the last sector even when playing on the easiest difficulty and can be an exercise in frustration. I've had encounters that were flat out impossible to win, where 3 of the 8 sectors in, I suddenly have 5 enemy soldiers on my ship and little ability to fend them off.
So, all told. A great idea, well executed, but the arbitrarily difficult random encounters and inability to save make a potentially great game merely a good one.