The only part of this game that gives me trouble is the bit where you zoom around on roller blades and spray stuff with graffiti. Other than that, it's all good.
Okay, so sarcasm aside, this is a pretty tough game. I did get a few more finger cramps playing it, but more than that, my progress has been slowed by brain cramps. So much of the game requires you to act with such near-perfect precision that even when I'm doing well, there's this knot in my apprehension that needs a couple of hours to relax itself out.
The big culprit, I think, is the grinding rails. They're only a couple of pixels wide, and while I think there's a degree of stickiness to them that attracts your character on a near-miss, the miss has to be pretty damned near because there have dozens of times when I've completely whiffed a jump to or from those fucking things.
Although, even that wouldn't be so bad, if it weren't for the time constraints. Especially in the race missions, you have little ability to plan and virtually no ability to recover from a mistake. The narrowness of your victory conditions can be pretty stressful.
Which isn't to say that I dislike Jet Set Radio, just that it takes a lot out of me, mentally. It's been a long time since I swore at a game, but this is definitely a "swearing-at" sort of game. Although, to be fair, I'm probably really swearing at myself. Perhaps the game is overly demanding, but perhaps the problem is that I let my focus slip one time too many and turn the possible into the impossible.
It's a line any difficult game has to walk - its challenges must feel fundamentally fair, but they must also push the player to their limit. I can't yet say whether Jet Set Radio clears the bar (primarily because of its unruly camera), but I've been making steady progress, and I'm just vain enough to elide the difference between "fair" and "allowing me to win."