1) In TGM, what the heck is "Uki mode"?!?! it seems to do nothing. 2) What the heck is this "Fanta Grape" business about?
"Fanta Grape" is an inside joke created when jago posted a picture of his Ti machine but had a bottle of fanta grape as the focus of the picture.
Yeah, Uki mode is just there to make clearing lines annoying. I'm pretty sure if you could force someone to play it for a long stretch of time with sound, you could psychologically condition them to no longer clear lines. Any runs in Uki Mode also don't get placed on the in-game rankings.
If there was to be any sense to be had from Uki mode, it would probably have something to do with the fact that the 1988 Sega Tetris prominently featured a monkey in the demo screen, and "uki" is a common Japanese onomatopoeia for a monkey's howl.
All versions of Sega Tetris feature a monkey as mascot, also the newer ones. I hadn't made the link, but now you mention it, it seems sensible. Also, TAP has monkey sound effects in the sound ROM. I found out before I knew about uki mode. I don't think there is any code for uki mode in TAP though, or if there is, it's unknown to us.
But since it is a cheat, will the game be stored in the hiscore? That's the question I am to busy to check it out.