I really enjoyed this! I didn't get very far but this game is really fun. And really great use of the theme. When I'm caught in one of those little boss rooms the confinement is real!
I am finding the difficulty a little daunting. I find myself afraid to use the bombs because of the damage from that huge blast area. I think the challenge is good but I usually find myself dying right before I see something interesting and new coming ahead. If the enemies occasionally dropped a health or maybe the bomb just pushed you away instead of doing damage, the opening stretch might be a little less intimidating. I could easily see someone dying a few times and quitting before realizing there are more than just the bats and skeletons.
Regardless of my struggle, it does make me want to get better and see more. I think this game is very fun and I think I'll keep this installed for a while.