I thought the demo was immediately fun, but that wore off about halfway through.
It then got a boost from the RPG elements, but I wondered - at the end of the game will my Wolverine be different than yours? Or will all options be unlocked at the end, it's only a matter of order? I guess the question is 'Depth' of the RPG elements.
I also was annoyed with not only how linear the game was, but how uninteractive the environment was. You can only jump/climb in very specific places, the rest of the game isn't actually 3-D, they're just 2-D wall maps. Disappointing for a next-gen game, I'm sorry.
I'd rent it or maybe buy it at $20, but I think even the $40 price tag talked about above is being overly generous.