It took a minute to get the gameplay loop in my mind, but I really liked the thought behind this. Starting off using 7 mushrooms to get a key, realizing I could accomplish the same thing with only 3. It was good game feel! I almost found myself racing my own time to see how efficiently I could get to the keys to streamline the process.
After beating the game, my mouse cursor disappeared and I had to close the game externally, and I felt like I didn't have the time to properly look at the room at the end of the game since I was trying not to get vaporized. What it did see looked interesting, so I wish I could've seen more. Great work!