Thanks for the feedback. I'm testing a new version with some changes:
... However the game is way too hard and the fact that you need to fire a shot that moves very slowly, and has to hit more than two or three enemies doesn't feel like a solid concept.
I raised the amount of ammo the guy has at the start of each stage. It was equal to robots/3. Now it's (robots/2)+1. Much easier. The shots now move faster, too.
Then, we also have the fact that the controls are pretty impaired. I don't mind eight or four directional movement, but it somehow seems unfair that the enemies can move in 360 degrees, and that they are as fast as you are. This could easily be fixed by not checking the direction they should be moving each step, and dividing and rounding their direction to an appropriate angle.
The enemies are now 4-directional. Makes them seem more robotic. (As in very clumsy. So I'm still adjusting that...)
However, even if you fixed this bit I'd much rather see this having a less arcade-ish approach. I'm a big fan of storylines ... The missing elements could be blended into this game without too much work if you linked the rooms together and added some smaller puzzles (keys and locked doors seem to already exist, but NPCs and more creative puzzles would be great).
I thought about that, but storylines probably aren't my strongest point as a gamemaker. I'll try to think something up, anyway.
Either way, I really like the graphics and would love to see more stylized games such as this from you in the future. Good job!