A pretty strong contained experience.
The scale switching conveys a nice sense of weight, power, and--well--scale. The slow nature of play fits with the theme, though I'm undecided about the (perhaps intentionally) awkward controls. On the one hand, since the monster can literally float in place and move backward, allowing the arrow keys to "flip" the player would make the controls much more intuitive. On the other hand, the current scheme does evoke arcade "Defender".
It has a good "Pac Man"-esque grind and chase game loop and doesn't overstay its welcome.
Great contribution guys and congratulations on the P-bot!