I enjoyed this -- few things I noted. just quick..
- It good you have a reason to not just keep your finger on the fire button. overheating mechanic is a good idea.
- It seems the pickups wont occur if you already have a pickup power. Took me a while to realize this and use your pickup powers ASAP as otherwise you wont get any other pickups. There is kind a tendency to hold on to the multi-shot until you need it .. I think you could make it activate straight away as it removes the flow of the pickups. or if not have a little tutorial text on first level to say don't hold onto pickup powers too long
- The drone was a cool smart bomb like idea.
- The waves a well done - Each enemy has there own way of moving through the screen and they reset to the top by the looks of it. A really good simple wave system.
- There seems to be an odd thing with the hitbox of the green beam shooting aliens -- it feels like every other bullet misses or something.. its odd.. but shooting that thing somehow feels different from the others.
- The green dive bombing alien that then goes in circle feels a little unfair.. you certainly learn to not be in the middle on the levels that those aliens are there. Maybe an arrow or something to indicate they are coming? then they could divebomb any part of the screen fairly to the player (they got to look out for indicator).
- The boss was very cool. Cool art and Great phases to work through. Not crazy challenging but felt like a good boss level effort to overcome. Im jealous.. my boss is not coming along well 8( - The health bar also cool