Of all the games I've tried this jam, I've easily spent the most time playing this one. I really enjoyed growing the obelisk, unlocking new attacks, and buffing up existing ones.
The first round I found very difficult. After that though, it seemed to balance out pretty well.
I think it's brilliant how most of the automated attacks for the tower are close range. It makes the game feel much more exciting because the enemies feel like they're swarming on your tower just before they get taken out by your defences.
I do wish there was more feedback for the player when a card was selected. I found myself double clicking a lot to make sure I had the power equipped and didn't accidentally click before the cooldown was up.