I played this though the other day, and I thought it was quite fun. I liked how you could look at the level as long as you wanted to begin with. I think that when the level resets you should also get as long as you want to look at it instead of it resetting when it wants to.
The one change that I would make is leaving the miner's hat where it lands if he explodes. That way it is kind of like the flags in Mine Sweeper - marking the mines. It almost seems like that was supposed to be a feature with the animation and everything being the way it is.
I also noticed that you were a big fan of U and Z patterns when making the levels. That made even the harder levels easy to memorize. Very good design choices overall. Well worth a 5. :)