Good job finishing on time!
Took a few minutes to figure out how things work, but I like the idea of reverse tower defense.
I've never investigated Construct, it looks interesting.
The controls and clarity of gameplay could use a bit more guidance for the player - I wasn't sure what I was or where the goal was at first. I'd say a bit more time on the visuals can go a long way to help with clarity. I also wish the music loop wasn't so short :)
After you get the hang of the controls, the gameplay is actually pretty compelling.