I love:
- Simple and clear mechanics, the goal is easy to understand
- Good ramp of difficulty
- Short levels so it's not frustrating to reset them on death or being stuck
I would have love if:
- There was more feedbacks on things happening (in particular when the red monster shot a projectile).
The core gameplay is classic (push box on buttons whith grid-based problems to solve) but it's well executed and pleasant to play.