Super Puzzle Fighter II Turbo
Ah yes. Super Puzzle Fighter II Turbo. One of the greatest puzzle games in all history. So what's it about? First and foremost, it features Street Fighter and Darkstalker characters in SD form namely Ryu, Ken, Chun Li, Sakura, Donovan, Hsien Ko, Felicia and Morrigan as the initially playable characters. The hidden characters are Dan (the weakest character), Devilot and the final boss Akuma.
Rather than just typical Tetris, one would put a crash gem near a gem to get rid of it. It does pay to gather a lot of gems together before getting rid of them with crash gems. Why? Well for every crash gem, it sends counter gems on the other side of the arena, which will not turn to normal gems until the number countdown is done for. The more gems popped at once, the greater the damage to the opponent which is a pretty interesting twist in Puzzle games. The rainbow gem pops EVERY one gem of the same color when crashed near a gem of that color of one's choice.
Also each character has a different type of gem pattern, Dan's being the craziest since his is all red. On the other hand Akuma and Devilot are typically cheesy since theirs is all about scrambling so much it's hard to counter them. So the best strategy is to always pop more than usual and keep attacking without hesitation.
The most challenging modes are the Street Puzzle Mode and Master Arcade Mode in which opponents get souped up to a high level as well.