Hydro Thunder is a game that first and foremost is about the fun. Essentially a racing game along the vein of Mario Kart, but with the cars replaced by boats (and sadly no power ups), you need to steer your little ship around a series of courses, aiming for first place. There's sheer drops, strong currents and giant angry vikings to contend with too, all trying to slow you down.
But while it isn't the kind of game that teaches morals and values, there are more than a few ways it'll test your child. Beating each of the races takes skill, persistence, and you can utilise concepts such as slipstreaming a boat by staying close behind it (and therefore letting the boat in front take all the air resistance - the commentators even comment when you do this), and it does test your basic understanding of the physics of water, as you try to angle your boat mid-air so you can land in the best possible way. It's a bit trickier than the likes of Mario Kart, as the bouncing waves can make your path a bit more unpredictable – but once you've got used to that, you should be fine. It's not realistic, and it's not the most educational game out there, but it is a lot of fun.
It's also a perfect game to play with kids. With four player split-screen on offer, and the ability to play as rubber ducks, it has that pick up and play appeal in droves. The simple controls mean anyone should be able to jump in (or should that be dive?) and start racing, as even our resident racing game novice managed to win the first few races, and always puts up a fight in multiplayer. The lack of any weapons also means you're unlikely to encounter any of the arguments that often occur between children when they're included - such as a child worrying they're being "picked" on, because someone keeps using a weapon on them, or seems to be going after them. It also means the races feel a lot fairer, and are often a lot closer, because no-one has any unfair advantages, leading to much less frustration by people who are less experienced.
Despite somewhat inexplicably being a 12+, there's nothing here, at all, that could justify that rating. Hydro Thunder is a racing game with boats - there's no violence, no gore, and no bad language that we've come across during our time with the game. There are no weapons that you can use to attack other boats, either.
The only thing that may make the game slightly unsuitable for younger players is the mild peril found in some of the levels - for example, on the Viking themed level, there are several giant vikings that lower their axes as your boat drives past, as if they're about to destroy your boat. Thankfully, they're not, and your boat just smashes straight through them, but this is the only thing we can think of that would justify this being anything other than a 3+.