http://insomnia.ac/reviews/playstation/tenchu/
Love this game. Too bad the sequel left such a bad taste in my mouth that I haven't tried any of the others.
About the review:
I like how the reviewer says the fighting system was "gimped" for the US release, as if there was any depth to begin with. Each character only has one main combo, which is a chain of 3 or 4 forward strikes. Yeah, the US version lets you mash, but there's only one attack button anyway, and I don't think tapping the same rhythm over and over is a significantly greater challenge. The enemies give no indication of when they're going to block, and there's no way to break their guard, so all you can do is spam attacks and hope one hits or hold block and counter-attack after they swing.
(You can slash to the left and right, or crouch and do a jumping slash, but those are useless in almost every fight.)
The 180 roll is definitely in my US version. I can't find a good online comparison of different editions, but Wikipedia (lol) says it was actually the initial Japanese release that didn't have the 180 roll.