It's good but if you can have the ps3 version don't go for this one.
Let's talk about the main part of the game, the Creations:
Definitely good, just not as good as you'd wish for. You can make many diverse stuff and give them your personal touch but some important features were taken out from the ps3 version and although you have many parts to choose from, at the start of the game, about 90% of them are locked;
Kart Creation:
It's fun and crazy, you can make your kart look exotic, muscle, and many more...including a goofy look or a mix of each. From the body to the engine, wheels, decals, spoilers, driving wheel and accessories all can be changed..but for instance decals can only be placed on the left, right or front of the car, you can't move them freely or make your own like seen on the ps3 version, witch is a shame and cuts some creativity from you.
Mod Creation:
You can modify the nose, mouth, ears, hair, eyes, clothing and put some accessories. Again there's lots to choose from but you can't place the parts freely. I noticed that the eyes some times get crazy and although you choose one shape they will change between the shapes of the same group. Beards will hide some mouths.
Track Creation:
The one i had most fun with! Unfortunately it as it's flaws too. Deforming terrain feels really fluid and changing the shape of the track is good. The problem here is with some parts of the decoration that just take space but aren't that noticeable when you're racing. Putting stuff around the track sometimes feels pointless because you reach the space limit and then realize the the track itself is empty with no traps, power ups or other stuff. You can't cross the track even if you change the elevation.
Gameplay:
I had a lot of fun, the drifting needs some tweaks but i think it's more a question of knowing out to do it right rather than it just being hard to do. There's a lot of stuff happening at the same time on the track, explosions, traps, high jumps and all of the action feels Great and fluid. Everyone that likes this racing kart games will love it.
Sound:
Commentary can become annoying! The music isn't that great...
Multiplayer:
Sadly i haven't tried it but i guess this will be great fun. You can play against 5 friends and each of you having your own mods and karts. With the host choosing the track i believe you'll be able to put them on your own tracks.
Graphics:
Very nice!! To see everything running smoothly on the PSP, with all the different mods, karts and everything happening on the track it's just amazing. Loadings are short!
Overall:
As i said on the review deck if you can manage to get the Ps3 version don't even think about getting this instead. On the other side if, like me, you don't own a Ps3 you can still have lots of fun with this version. There's lots to do, from creation to achievements, story mode and online. Lots of replay value in there.