Tetrex
This is another Tetris for the Rex, and it's in many ways a better game than MiniTetris. Controls are much more responsive, graphics are fancier (not really something to factor in, but worth mentioning anyway) and removal of lines is much quicker. Tetrex also drops the block all the way when you press the drop button, which is nice but was confusing at first when you expected it to just move it down faster :-) ...
However, there is a serious problem with Tetrex. It breaks the formula! The first thing you notice is that there are a bunch of randomly placed squares at the bottom of the playfield already when you start. Each time you go up a level some more appear. Very annoying from a purist's standpoint. But here's the real pain: the four piece straight blocks are only three pieces! I don't think I can forgive Tetrex for this, I sure can't think of any good reasons to do it like that. It's just wrong ... One more negative point: something feels a bit odd with the rotation (the rotation point doesn't seem to be centered in the blocks) making it slightly harder to place blocks to the far left if you need to rotate them first than anywhere else.
So, it's not as faithful to the original as MiniTetris, and I don't like that. However, it has much smoother gameplay which makes it nicer even though it's not true to the formula. If MiniTetris is released in a new version (it's been hinted at) that is smoother and speedier I will definitely prefer it before this. Good game, but not pure enough :-) ...
