Cool game! It's pretty rough, but the setting and vibe are super interesting and diffusing into walls is great. To me it kinda switches the game between being a platformer and a top-down game, and you have to reinterpret the level in your head.
I love how open it is right from the start, how you can just wander in any direction and find something interesting. Reminds me of Zelda 1.
Some thoughts:
- I think the game is a bit too unforgiving, and it wasn't clear when I hit a checkpoint that I would return to.
- It's not clear which enemies can hurt you while you're in a wall. I couldn't figure it out and I always felt like I would randomly die.
- The transition in/out of walls feels too slow. I think speeding it up a lot would improve the feel, and also prevent some of the times when you can't get out of the wall without being caught.
Overall, nice job!