[gdl]

Oh, absolutely. And a lot of those are choices to make and fine-tune rather than obvious boolean working/buggy issues. ie The Tetris Wiki lists a half-dozen different rotation systems alone, some of which show fairly complex behavior (http://tetris.wikia.com/wiki/TGM_Rotation). Add in getting the controls and timing just right, and a simple puzzle game becomes a lot trickier to pull off than it might seem.

Oh, and yours isn't all that bad. I played through an entire round without quitting out of boredom or frustration with the controls, which is better than I can say about a lot of random Tetris clones out there. Or maybe I'm just more forgiving of games that openly admit to being stupid and unoriginal ;)