I’ve been playing this for about two weeks. It is VERY addictive, challenging, and frustrating. The 3D format is a great challenge, but also really hard on my eyes. I have to limit myself to about 20 minutes a day now. My biggest complaint is that every so often while I am playing, a 15 second advertisement pops up without warning. This is annoying, but more than that, I lose my concentration. At level 60, this happens about forty times per puzzle. As the puzzles get larger and harder, I found myself using the Hint button more often. Watch 30 seconds of advertising and it will remove 3 blocks. Eventually, that became 75 seconds of advertising, which isn’t worth it to me. Really fun, clean programming (no glitches), easy to learn, but also very frustrating.