Not too bad, but there is plenty of better Tetris and Breakout games by our days.
If what you like is the funny crossover between Tetris and Breakout, rather check out the one from "free-hard-games", which is way more polished and has a more interresting gameplay.
(if links are allowed : http://www.free-hard-games.com/tetris-breakout)
The problems in this Breaktris are that gameplay is not smooth/handy at all. Tetris is playable but remains quite rough (cant move near walls, etc.), and the breakout itself is a fail :/
The paddle doesn't move fast enough, and bounces are so screwed that you can't play correctly
Also, destroying your tetris construct (and then returning to tetris) is quite counter productive, since a perfect build can be ****** up by the breakout, leading you to... suicide asap when you enter breakout mode.