There are a lot of different ships, guns and other equipment pieces you can find and use. There are also a lot of characters who can join you. Each of them gains experience and can develop their skills in various ways.
Combat system is distantly reminiscent of Final Fantasy's active-time battle system and combat system of FTL: Faster Than Light.
For those seeking extra challenge, bosses feature "epic" versions, that are harder to defeat, but bring better rewards and, of course, unique achievments.