As you travel in the world you are allowed to take three monsters around with you at any given time; every other monster you own is sent back to the Monsterium in Star City on Star Island for safe keeping. Those that you keep with you will gain a few experience points for every race you win whether or not they participated in it. Choosing monsters carefully before setting off can be incredibly important, not just to make sure you're leveling up the right monster, but so that you have monsters who excel at whatever terrain your racing on.
Different race courses are created out of different material, some have water, others lava, others sand or dirt, etc., and different monsters respond differently on the various tracks. In order to be a successful racer, you need to make sure that all of your monsters have leveled up as much as possible, so that should you come across a grass-based track late in the game, your grass track running monster is up to the competition. Additionally, extra items can be purchased to enhance your monster's stats which fall into four categories: speed, thrust (acceleration), power (damage your monster can inflict during a race), and spirit (ability to withstand attacks and fill turbo gauge). Loyalty and will are also factors one has to keep an eye on (win all your races though and you'll never need to worry about either). As you progress in the game you can even try and breed monsters so as to get ones with characteristics which will better aid you in your monster racing.
With simple controls and minimal use of the touch screen, which is mainly used to provide attributes about monsters and your location in the world, the game is playable by all. It also tends to be very easy early on, something which belies the later difficulties one will encounter if they haven't taken on every single race available (sometimes two or three times as items and monsters in the wild respawn) in order to level up sufficiently.
It is an enjoyable twist on the basic gotta catch'em all philosophy, and the use of races instead of innumerable mini-games ought to help the title find an audience with those who dislike repeatedly tapping a bullseye or spinning a little ball around. The game can be saved at any time (except during a race), and the number of races, monsters, courses, abilities, and items available ought to keep those who strive for 100 percent completion busy for an exceedingly long time.