Building ship, trying to come up with some nice ship design was a lot of fun.
Fighting could be improved by for example faster bullets from your ship (I missed shots so many times), or by having enemies with really low health so you can get some scrap back. I got to a point where I got only one gun left and because even the smallest enemies wear shields I almost wasn't able to kill them.
But the game is nicely designed, some little tweak to fighting could make it a good game.