I change algoritm of creating enemies to more simple. Before it used more and more memory over time. I hope this will a bit quicken game. Also I decradase a damage of missile explosion ;)
I add new type of enemies. In future probably you will can upgrade weapons, by levelling up AND power Ups (but this will upgrade weapon only for few seconds, and level Up will be permanent).
Thank to everyone for comments :)
I corect size of ship hit box (and also change the graphic of it). And I ad laser weapon.
New type of enemies will be in feature. Please check for updates!