The humble slime is an icon among monsters in the console role-playing world, having appeared in each and every Dragon Quest game since the series' inception. The little blue blobs are yours to control in Rocket Slime, and the result is an action adventure that plays out much like the slimes themselves: simple, easily defeated, and adorable almost beyond all reason. This isn't a very complex game, but it doesn't really need to be, and it makes a fun little outing both for longtime series fans as well as habitual monster collectors.
The game revolves around Rocket, a cheerful young slime who's enjoying the good life in the peaceful blob capital of Boingburg--that is, until a crew of bushy-tailed monsters called "the Plob" move in. They're looking for a powerful artifact, and when they don't get the information they desire, they kidnap almost every denizen in town, bomb the town to rubble with a giant tank, and leave. As you might guess, the one slime that escapes capture is Rocket himself, and you soon set out on a journey to rescue your friends and fellow townies. One lone slime battling powerful plobioso with battle tanks seems a little unmatched at first, but in the Tomb of Tootinschleiman (yes, it involves slimes and a flute--don't ask), Rocket unearths the powerful Schleiman tank. With this legendary slime-shaped, grinning piece of weaponry, Rocket can easily match the strength of his foes.
So, your basic objective is to save all your friends, and there's a couple ways of doing that in Rocket Slime. The game consists of a couple of different modes. An action mode lets you hop around a number of locations on the island of Slimenia, platformer style; the tank mode lets you climb into the mighty Schleiman tank to do battle with the equally imposing tank of your opponent.
During action mode, you'll be moving back and forth between your home base in Boingburg and whatever area of the island you're choosing to explore. Rocket has a number of simple moves, like hopping, floating, stretching, and the ability to carry a number of items on his head. The DS touch-screen isn't actually used for any gameplay outside of a painting minigame, so these controls are handled exclusively by the d-pad and A and B buttons, which works just fine. While it's a limited moveset, the game does a good job of introducing a number of different ways to use a single move. For example, stretching Rocket out and then releasing the button causes him to catapult in the direction he's facing. This move is good for breaking small obstacles and attacking enemies, but it's also how you throw things in the air for Rocket to catch, and in certain areas you actually have to bungee Rocket from a number of elastic cords to navigate. Carrying items is an important slime skill; it's how you move rescued slimes to safety, collect items and monsters for transport back to town, pick up weapons and ammunition, and solve certain puzzles. A nice touch is that you can stretch, float, and attack enemies while carrying things (even though you'd think such a little slime would be burdened while carrying objects). So while the controls are very simple and easy to master, the versatility of these moves helps things from getting so easy that they're dull.
While there are a few proper boss battles in action mode, most of the game's big conflicts are carried out via tanks. The tank battle mode has you running around in the Schleiman tank, loading up on ammunition and firing it at your opponent. The top screen shows an outer view of the two tanks facing off, shows all projectiles in the air, and shows any incoming enemies or moving allies. Tank health is also displayed here, so you can see how much damage you're inflicting and taking. Your tank has two cannons, one that will fire straight at the opposing tank, and one that fires upward in an arc. If your foes are shooting at you, you can knock their missiles out of the air with your own. Tank ammunition is composed of items that you either find in the action stages, or that you make yourself with alchemy. While most give straightforward damage, there are also items that can mix things up, like a shield you can launch that will soak up three or so hits before falling, protecting your shots behind it from getting knocked out of the air. Holy water is useful against ghostly projectiles, and so on.