Siren (that's what it's called here too, I just blindly assumed that it was called Forbidden Siren everywhere else as that's the Japanese title) is actually a pretty good game. I think a lot of people just have a problem overcoming it's difficulty and change of pace. It's like a stealth survival horror game, equal parts Silent Hill 1 and 2 mixed with Splinter Cell. Most of the characters that you play, of which there are ten, don't have weapons or are we disabled (one girl is blind and you have to use another character to guide her around). So you're forced to crawl silently along so as to not be noticed by one of the "zombies", who can kill you hardcore without a problem, or you could always run away or distract them. Plus you can use this ability called sight-jacking where you can channel in on their thoughtwaves and see that they're seeing. You can study their patrol routes and figure out how to get around them judging by the lighting conditions and their path of vision.
The graphics are pretty good too (kinda like an updated Goldeneye look, with human actors faces transposed onto polygon models), though a lot of characters look like they're from the 70's and one guy looks like the Iron Chef. The sound effects and ambience of the game are phenomenal. Problem is, the voice acting is terrible. I noticed one review where the guy basically praised the game and it's innovations, yet gave it a 5/10 because of the voice acting. It's really bad, and I mean "You, the master of unlocking." bad. It kinda ruins things but it's a good game nonetheless. The average score ratio at Gamerankings is a 76%, and that's not too bad considering the games flaw.
http://www.gamerankings.com/htmlpages4/918848.asp
So if you're really into Silent Hill and Splinter Cell and can deal with laughable dubbing, get it.
As for Onimusha 3, the original vocal track, from Japan, is in Japanese and French, not just the accents. Jean speaks in French in the beginning of the game and is later bestowed with the ability to speak and understand Japanese. The original Onimusha had the option of playing with the original Japanese voice track with subs, as I wish all games would as it just feels more authentic that way.