Great game, putting together the ship could get a little annoying (because it was hard to select what you wanted) but that was only a minor drawback that can be fixed in Upgrade Complete 2!
I agree with the color coding idea that'd be great, also i haven't played much this might already be in there but ability to speed up the waves. My bad if that's already incorporated.
 "William and Sly"){kind=icon}
 "Perfect Balance"){kind=icon}
 "UPGRADE COMPLETE!"){kind=icon}
 "Desert Moon"){kind=icon}