Good game but...
I found many flaws in it.
1.) Way to easy! I like how you made a nice simple game but it really was no challenge for me at all.
2.) You should have to different ship classes that have their own special upgrades to make them different. Also, you need to have a health and SP upgrade.
3.) You need different levels and maybe some more enemies, fighting the same things over and over was boring and more levels would be a lot more fun, maybe have achievments as well?
4.) Different weapons, for different occasions. Heavy, medium, light, all that and they should have their own set of upgrades, also you should have defensive things as well, such as shields.
5.) The music gave me a headache. It was awesome music and I loved it, but after about an hour it was annoying, you should have different music tracks to select.
I feel like a jerk saying all these flaws so i'm done, other than that though i really did like the game it was pretty cool!