In short this is the best Kart racing game i have come across that i would slot into the "Fun Racing," genre.
As i myself am not to adept at the mainstream "serious" racing game i found this a great relief. Going back to my days of playing "Crash Team Racing" and "Crash Nitro Kart" i thouroughly enjoyed the gameplay. Each character has their own all star moves which are awarded throuought races, and you collect "Sega Miles" as a type of currency to buy the extra content in the shop.
There are a few modes in game. The first being single player where you are given the choice of Grand Prix, Missions, Single Race or Time Attack the standard stuff. The missions start easy and gradually get more difficult, Though not so difficult you start pulling your own hair out.
The Multiplayer is quite easy being able to choose Online or Split screen, The split screen can be then customized to different game types, such as Race, Battle, Knockout, Kind of the hill and so on. The online multiplayer is quite fun and is what you would expect from this type of game.
As for the achievments some will come through gameplay, Such as the various coloured licences and playing on every track and time attack achievments, however some will have to be worked at. (Such as using specific All star moves on Specific characters.
All in all i thouroughley enjoyed playing this game and will be bringing it out on many a gaming night with friends as a bit of a fun thing to do to diver from all the serious racing games out there.
(EDIT) After completeing all the achievments for this game i realised that the actual achievment for doing so had not unlocked. When i checked the in game achievment progress menu i realised that for some reason it wa registering that i had not done everything (even though i clearley have a i have the actual achievent for it) I do not know if thi is a glitch or if its something i have done. But i am now going to have to re do the whole game as one of the ones i have already done is impossible to do again. ( I need to buy an item from the shop and i have already brought everything so there i nothing there for me to buy)
Although this has not ruined the game i am lightly disappointed as i feel i have been cheated out of my 1000/1000 gamerscore