Incredibly fun game. It starts of pretty easy, then you hit the wall. It gets very challenging very quickly. The controls are pretty well done. And the music is insanely addicting. It did not take very long to fully upgrade my ship, so IAP is not at all needed. I would, however, like some varying game modes for single player.
Not sure if it would take away from the challenge, but I would love to see an opportunity during the wave mode to get some type of energy increase pickup. It's kind of punishing as you get further into the game.
Thanks for the awesome game. And info on upcoming changes/modifications would be much appreciated.