I greatly enjoyed it, I wished you could add the option to enable some sort of indicator for the shooting direction (until I got the hang of it, it was pretty hard to aim).
I guess you could also add other types of smaller ships to choose from with a forward cannon or for ramming purposes to add more variety.
The "roguelike" part of the game feels very underwhelming, so I'd suggest to focus on the mechanics and the variety of things to do instead, since it has potential for a nice long campaign.
Nevertheless it was great. Keep it up.