Solid Gameplay, irritating presentation, lack of decent modes
Tetris DS at its core features solid and enjoyable 'Tetris' gameplay, with the expected Marathon and VS CPU modes along with the bonus of 2 and 4 player online play. However it's the quality of this gameplay that further accentuates my gripes with the game.
As trivial as it may be, I can't help but be a little irritated every time I have to experience the relentless and hyperactive nostalgia present in almost all modes, with every level containing animations and sped up music from old Nintendo games. I find myself wishing that the game's designers had gone for a simpler, less in your face approach, with cleaner graphics and perhaps more space devoted to the actual play field.
My other gripe is that outside of Marathon (and perhaps VS CPU) mode, none of the other single player game types are particularly enjoyable. This is mostly due to their gameplay having very little to do with Tetris and as a result they feel more like half-baked afterthoughts than decent ways of adding some variety to the experience. Even just a couple of time based modes that could provide a break from Marathon would have rounded out the packaged pretty nicely.
All in all this, despite my gripes, is an enjoyable game of Tetris and while my skills have always been rather average at best, I found this to be the first Tetris game that has had me addicted enough to actually improve and therefore gain even more enjoyment from it.