Tetris Marathon. Another Tetris clone for the 83+ family. And by far the best.
Implementation: 9.9/10 With drop shadow, hold, and a 5 piece queue, this version of Tetris easily holds winner for most features and faithfulness to the original. The only problem is lack of lines clear information in-game, and no customizable options, most notably scrambled lines, which level to start on. There is also no twoplayer mode, but I don't feel that that's much of an issue
Gfx: 9.8/10 Grayscale=yummy. Line clear animations are nice, and each piece has it's own design and gray. The only complaint I have is that some of the pieces' (namely the square and line piece) outlines are the same level gray as the dropshadow. This makes for a slight difficulty in viewing the difference between the blocks and the shadow. Also, the title screen could use some jazzing up.
Ease-of-use: 9.9/10 Manageable size (5k or so) and compatible with MOS makes good. Controls are the same as Ztris, so no problems there. My only complaint is the fact that Clear returns to MOS rather than the title screen. Usually I only use clear (in ztris) to start over a new game, so this is kind of annoying.
Average: don't feel like quitting out of tetris to calculate it, so I'll just say like 9.87/10