Great job! I really liked the way the doors lead to different upgrades - I think that was a unique way of incorporating the theme. I got to about wave 15. I think in general the game plays well enough and I really dug the music that started playing around the time that I got to wave 8.
If you plan to expand it, maybe add drops in the actual level or have additional enemy types. But I understand that you were under time restraints for the jam and this is a solid prototype that you can definitely expand on!
Nice work and thanks again for playing/rating Untangled!