Easy to grasp, easy to play, all you need is cards, 2d6, pencil, paper, and you. I love solo games, but as most solo rpgs are actually 'journaling' games, this is a nice change of pace. Also it looks very easy to hack, if after some replays, you want to change up rooms or items. Always a bonus.
I'm very biased cause I love Tunnel Goons (who doesn't?) and I love Skullfungus. Mix them both to make a game about playing a bunch of shrooms on a mission? How could that not be awesome? Well, it is.