very cool idea. i liked the use of physics and scale.
some stuff that could be worked on if you've got the time:
- it'd be nice to have a way to pause/close the game instead of relying on alt+f4
- i toggled the mute button twice (muted then unmuted) but there was no music while playing
- i feel like the projectiles from the turrets should be blocked by the physics objects (unless they already are, in which case sometimes they don't block projectiles)
- the sign in the level where turrets are introduced is missing a word
- it's not always clear that you can scale the same object multiple times (i encountered this in the same level as above)