Sorry, old ctrl+v, whoops. Editing now, typing from memory.
I am spamming my thread, I know.
I have optimized the game as you suggested (I think I got em all, or at least mostly) and some my own optimizations.
I decided to give it in a try in cocoonjs, not really excepting anything. But now it runs at 45-60 fps, before 5.
I notice, the more blocks one level has, lower fps. As the blocks disappears, and less collision checks to do, higher fps. naturally.
Fifth level is ice block level and that's the slowest level, only 25-30 fps. And I spotted a couple of bugs there too. Other than those the game runs as it should.
I feel more optimistic now. Thanks.