Bad.
The controls are slow. You can't turn a block and move it sideways at the same time. The screen is too big. It doesn't feel rewarding enough. It speeds up to where it's impossible to get anything out to the sides.
But worst of all: THIS IS NOT TETRIS.
Tetris comes from the word tetra, whitch means four. There are a few shaped in the game, each consisting of four blocks. Since some blocks are three and some five, by defenition, this is not tetris.
Also, it just generally zukz ballz.