Story: You're an up-and-coming tennis player attempting to win the four Grand Slam tournaments.
Gameplay: Create your own player (complete with daft haircut and designer gear) then go play tennis by swinging the wiimote. Timing dictates which direction the ball goes. A combination of button presses and angle of swing determines the type of shot played. Using the d-pad sends you towards the net or baseline. The Wii moves you automatically towards the ball unless you attach the nunchuk to do it yourself.
The Wii MotionPlus unit can be used to give more accurate control.
Save System: Regular auto-save. (Not that you're likely to achieve anything much worth saving.)
Comments: The main feature of Grand Slam Tennis is that it's the first game to utilise the new Wii MotionPlus accessory. This clips into the nunchuk port of the wiimote and allows the Wii to reproduce proper 1:1 movement. A normal wiimote detects how fast it's being moved and in which direction but Wii MotionPlus introduces position detection. With WMP, the Wii can tell where the controller is, not just what you're doing with it. This should make the hand movements of your character on screen follow your own perfectly. Thus, in a tennis game, shot selection merely becomes a question of holding the wiimote in the correct position.
Except I don't actually have a WMP unit, which makes this review somewhat tricky. Then again, if you're thinking of renting the game, you probably don't have one either. Also, even if you do buy the game with a bundled Wii MotionPlus, you're unlikely to have extra units for multiplayer. It's still worth knowing how the game plays without WMP.
The short answer is that it's really hard.
Frustratingly, punishingly, exasperatingly hard.
Even on the 'easy' difficulty setting.
In my first hour of playing, I won two games. (That's games, note, not matches.) On easy. Nonetheless, this left me sweating and with a worrying pain in my elbow. I gave up trying to play the game in any fashion approximating real tennis. I sat down, rested my arm on a pillow and flicked the wiimote with my wrist. This didn't make much difference to my success rate but I felt it reduced the likelihood I'd need surgery afterwards.
There's more depth to the tennis than in Wii Sports but the difficulty is off-putting. It's easy to hit the ball but computer opponents return any kind of standard shot without fail and so rallies go on forever unless you take big risks. This normally ends in ignominious defeat rather than success.
The only break from the tennis is to play more tennis, either against legendary players or with 'amusing' altered rules. There are no mini-games to practice skills. This is bizarre, since even Wii Sports has some and in many ways they're the best bit. Despite all the licensed players and tournaments, without WMP, Grand Slam Tennis doesn't really offer much more than the game you got bundled with your Wii. It's also more annoying.
Conclusion: Rather than renting this, you'd be as well to dust off Wii Sports, unless you really, really have to play against Andy Murray at Roland Garros instead of your mum's Mii in Nintendoland.
Graphics: The stylised, cartoony graphics are pleasant and do the job well. Creating your own ugly no-hoper with poor fashion sense is always fun.
Length: Until your elbow starts to feel sore.