Fine game, works fine. Now I'd like to see the concept pushed further, with upgrades and why not a bit of story line.

this game looks very nice! love the concept though the controls are a bit confusing sometimes, maybe making them drag and drop would help a bit :3

and like horobi says, upgrades and a more features will make this game even better ^w^

Nice game, but misses something to keep going.
And the screen after every stage is nice but could be better.
Maybe add an extra feature. Like a military space defense tower where you can do research and
develop some upgrades. Idea´s: Plasma canon skin upgrades / Plasma beam upgrades / something extra that explode some plasma cells randomly when activated
And I´m not saying to do all of those things.
Do whatever you might feel whats cool, just one is enough.
Upgrades keep you going.