Army of Awesome!
A very fun and engrossing game. Very skillfully made, too. One thing I had a small problem with was that I kept running out of laser ammo when fighting the Mammoth tanks. Maybe in the next game you can give the player the ability to purchase greater ammo capacity for all weapons. In fact, you could add all sorts of purchasable upgrades, like quicker firing speed, more powerful shots, and more a higher life energy maximum. Of course, the game is already excellent as is. All that extra stuff might just clutter it up.
Either way, just a suggestion. Great work!