Mmm, I'd have suggested
Azel: Panzer Dragoon RPG, on the grounds that the Japanese release is MUCH cheaper, but it
is a bit wordy. Menus and those moments where Edge talks to himself might be tricky. At least all dialog is spoken Japanese (barring the opening and ending, which are Panzerese)?
Same with
Burning Rangers - Japanese version is cheaper, but because you're having directions barked at you by your navigator, knowing the language is kind of important.
Radiant Silvergun is a great Japan-only shmup, although it's probably gonna set you back a bit ($100 at
least, probably more like $150).
Fighting games are a dime-a-dozen in the Japanese library, and they can be quite good given the expansion RAM and such. I know a lot of people swear by the Saturn ports of
Street Fighter Zero 3 and
Marvel Super Heroes vs. Street Fighter, for instance.
Apparently the Japanese version of
Doom is better than the US/EU version. I only have the former, not the Western release, so I can't comment. Although,
Seireki 1999: Pharaoh no Fukkatsu is a pretty darn good FPS you might be interested in (
PowerSlave in the US,
Exhumed in Europe).
Darkseed 2 is on the Saturn in Japan for some reason. I don't recommend it (
watch the Wrongpurae instead), I just thought that was amusing.