Not too shabby! Gameplay concept kind of makes me think of Bomberman but with more steps, or an interesting subversion on the Qix genre.
I admit that I feel like the gameplay feels rather half-baked at the moment as it is easily exploitable with lame strategies and doesn't feel like it evolves at a significant pace or in a way that makes the gameplay change and introduce new tactics. I know it's a game jam game so obviously I'm not expecting much, but I still feel like we haven't fully uncovered the potentially fun core of this wall-bombing gameplay you've introduced here, only having scratched the surface.
Having said that, this game is a great example of what I like to see the most in game jams: instead of sticking with something normal and safe, you experimented with a wild and creative mix of mechanics to see if it worked, and despite my grumbles before, I still had a decently fun time with it in its current state, so I consider that a success.
Even more so, it really gets my imagination going for what the game could evolve into. For example, what if the trigger to explode walls actually came not by player detonation, but when you intersect a vertical and horizontal wall, similar to how you block out sections of the map in Qix? Or, what if there were some sort of combo system where explosions that occur from multiple walls being constructed or intersecting give more points, or do more power which is necessary to defeat foes with large regenerating health? Lot more to experiment with here and if you do so, I'd be happy to play it!