My feedback for Nano Defender:
What the game does well:
The player actions are responsive.
The dialog objects do a good job of teaching the player how to play in the early levels.
What the game doesn't do well:
The ship's movement versus hostile projectiles; There's a lot of projectiles (especially the bacteria) and the ship movement remains constant. The problem here is with how fast the ship moves with no way to move more precisely
Areas of Opportunity:
While the game does really well of incorporating the 'inside' part of the theme, I believe more can be done to support the 'out' part.
To improve the movement you can do one of two things: 1) add Gamepad support so that the ship's movement is analog and not digital or 2) lower the ship's movement so that more precise dodging is a viable strategy for defending oneself.
I hope this feedback helps!