This post could make me go insane. There are a TON of Japanese-only PS1 releases that are so good. Tell me a genre and I'll list a few. Shooters of course are my favorite and there are a lot of them. I think I own 1200+ Japanese PS1 games, and I usually only keep the playable ones (I won't ever play those dating sims or hard-to-understand strategy/rpgs or even those pachinko games). Japan has more DDR games than the US, they have Martial Beat which is like DDR with karate moves. Someone mentioned Gunners Heaven which is probably my favorite game on the PS1. Japan has cool accessories like ZXE-D Legend of Plasmatlite which comes with robots that you assemble the way you want, plug them into the PlayStation and then your robot appears on screen and you can fight with it. They have the Blockids release which comes with a special controller (it's a dial like used on Arkanoid). In fact, this controller works on both of the Arkanoid releases in Japan giving it a real arcade feel! And I love Arkanoid! I don't play the Japanese RPGs, but I did fall in love with Popolocrois RPG and completed it! There's even some games that were supposed to come out in the US or Europe but only were released in Japan. (Mortal Kombat 2 is one....awesome game....Beavis & Butthead in Virtual Stupidity another....etc)

Should I list a bunch of games and you guys can ask what they are?