I played to around 20,000 score. The game feels easy and does not seem to really get harder over time. It feels a little odd that you can disappear off the bottom edge of the screen, this is not a huge issue as bombs can spawn there as well, it just looks odd. The game is intuitive and easy to learn though especially with no difficulty progression gets boring over time, that is why I stopped at 20,000 score instead of going further. I think that having some different shaped and sized bombs would help with some of the boring-ness. Also having a looping background texture would help a bit.
-R