I thoroughly enjoyed the animation, lighting, effects, and dynamic music.
The game was a bit difficult to understand. I was unsure of what I was supposed to do and why via the design. I knew what to do with the familiar controls/perspective, but there's no indication of how long your summon lasts, if that summon joins you to the next room, etc. During my first playthrough, I died upon entering a different room (fighting enemies) from the starting/tutorial room, so I naturally restarted and pushed through a different door to see what it was all about.
When upgrading at the second "shop" room, I didn't really know what each summon was useful for or what direction I should take. At one point I had 8 gems to upgrade, but when I spent 4 and had 4 available, the "costs 4" upgrade button was greyed out for some reason.
Everything sounds and looks great, but I think a small bit of UI polish and hitbox refining would make this even better.
It's a very impressive entry. Great work to your whole team for churning this out in such a short time. :)