Indeed the best MK "action-type" game, but still falls a bit short...
First is the gameplay. It will take you a while to get used to having multi-directional attacking, and then the combos will take some work, but its mostly just button mashing, so you should pick up on it eventually and get triple-digit combos. But I HIGHLY recommend playing as Kung Lao. His moves are much easier to adjust to, and his attacks aren't so... monkey-like. They're pretty straight forward, so you shouldn't have any trouble picking up his move list quickly. Liu Kang is too spastic, and juggle combos... and combos in general with him take too much effort and tend to only connect the first couple of hits. Its a shame really, but trust me, if you don't want to be easily frustrated at MK: Shaolin Monks, then use Kung Lao. The special moves are nice and easy to pull off... just hold the R-button and press one of the attack buttons and there you go. But they're really only necessary during some boss battles. With the regular "cookie-cutter" enemies, combos work the best.
Another is some of the seemingly impossible situations they occasionally place you in. 5 Takatans attacking you at once is sure to have a negative effect on your health meter. Some of the puzzles are too easy, while some bring you close to pressing the eject button and skipping the game down the street.
Mortal Kombat: Shaolin Monks is a good rental, but unless you just absolutely worship the series, then don't drop the green to own it. You'll wind up returning it or even worse, having to get trade-in value for it, in which case you lose out on that cash you blew on it.