You'll be guiding Rocket through your tank, picking up ammunition and then tossing it into your cannons, handling all the action on the bottom screen while you watch the overall flow of battle up top. Everything's in real time, so you'll have to react to your enemy's salvos as they happen. This can start to make things a bit chaotic, but as the game goes on you'll have the option of adding different slime buddies to your crew aboard the Schleiman, each with their own special abilities. Some will help you load ammo; some will attack the opposing tank on their own; some will heal you. Your teammates come in handy, especially as ammo flies fast and furious in some of the tougher tank battles. It's another simple system, but one that allows for a fair amount of variety and even some strategy as you work to sneak your shots through to the enemy tank. Once you've reduced their health to zero, you can hop over to the other tank's engine room and destroy their engine to bring an end to things. Tank battles are engaging and often comical, particularly when you load up your friends in a cannon and blast them at your foe.
There are 100 slimes to rescue, both from the game's stages and certain tank battles, but they're not the only thing to collect in Rocket Slime. You can send not only your friends, but also enemies and items, back to town for sorting. Capture enough of one type of enemy, and it'll become a statue in the town's museum. Items can be used for tank ammunition as well as components for alchemy, which lets you make newer and more-powerful things. As you rescue slimes, Boingburg becomes more and more bustling and fills out with a few minigames, which you can upload as demos through the DS's wireless capability to people without the game. You can also play wireless multiplayer tank battles with up to three other players who own the game, which lets you select any tank you've previously defeated in battle and customizes your tank hit points and other parameters. Pitting slime tanks against each other is quite amusing, and since you still have to board the enemy tank and bypass any internal security to administer the coup de grace to the engine, a win is not necessarily guaranteed, even if you hopelessly outclass your friend's ammo.
In presentation, the game is vibrant and colorful, each slime and monster distinct in appearance and possessing a variety of endearing expressions. While the stages aren't what you would call awe-inspiring in scope, many possess their own particular look and feel that works in the cutesy milieu of the game. From the tanks--who look like giant versions of Rocket Slime's cute monsters, only bristling with gun cannons and sporting Band-Aids if they get too damaged--down to the most microscopic slimes you have to rescue, or the way cat enemies will sometimes ignore you to play with a piece of catnip, a lot of personality oozes from the game's visuals.
That personality is matched by the upbeat music, which reprises many classic tunes and sounds from the Dragon Quest series, as well as the writing. There are a large number of slime puns in the text, from Tootinschleiman to the blessed Mother Glooperior and everyone in between. Some of the turns of phrase are a bit on the dopey side, but when you're talking about a game based on the adventures of a bunch of grinning blobboids, it's hard to take anything too seriously.
The game itself is average length; with the ease of gameplay and how straightforward the game's stages are, you can easily rescue most slimes and overturn the Plob in about 10 or 15 hours. However, there are a number of out-of-the-way items to collect, monsters to gather, alchemy recipes to dig up, and other such tasks to encourage you to fully explore all over. So while the game's not difficult by any stretch of the imagination, it does a good job of pacing itself and providing some neat little diversions. If you're one of those people who likes role-playing action with cute critters and a "gotta catch 'em all" mentality, this game makes a good fit. Likewise, if you're a fan of the Dragon Quest series, particularly those smiling little blue gloops, there's enough nostalgia and genuine amusement to make Rocket Slime worth checking out.