Right from the start, I was addicted to this game. It's simpliciy is its charm, and I could literally play for hours. And indeed I have, for I just now 100%'d the game - it is very rare that I feel the inclination, or have the determination, to actually do that, especially given the sheer number of trophies available in the game.
But that's a testament to how enjoyable it is. The controls are absolutely spot on, graphically the game sits very well with me (being a fan of oldschool sprites), and the music, though repetitive, does not become even slightly annoying, rather serving as an excellent backdrop to the action, and the SFX are perfect too - the huge chain of explosions one can hear shooting at a Vesssel is very satisfying indeed!
The levelling up system is nothing short of brilliant and I worked very hard to come up with the optimum order that I now use in order to get the best results. The differing enemy types lend an excellent level of variety and force the player to think carefully about their movement and attack plans.
Even after having finished the game, I fully expect to come back and try to beat my own high score - being merely 6th today (at the time of writing) simply will not do!
The only flaw I can find with the game is that it really, really starts to hurt my mouse-hand after playing for a while, as the gameplay very much demands holding the fire button down once the real hordes start showing up, but this is a minor issue really, and it is literally the only one I have.
Truly excellent work!