FTL has some standard achievements for progressing in the game and winning. These are kinda boring. But it has a raft of other achievement for doing special feats in the game. Like getting to the end without firing a shot, or setting all of an enemy's rooms on fire at once, or killing an enemy from health during a single cloak. They tend to teach different playstyles or encourage special challenges. They add a bit of fun, without actually being required in the game.
A lot of roguelikers try these sorts of things anyway - win without food, or speedrun, or pacifist run, etc. But it's nice to have them legitimised in the game.