Mister Slime is a simple 2D platformer that casts you as Slimy, a giant green head with four stretchable arms that is stuck doing chores for the local tribal leader. When he is finally able to sneak away, young Slimy ventures into the neighboring forest on a quest to find a friend, and en route embarks upon a historic journey to determine the origins of an ongoing war between the slimes and the axons, a neighboring tribe. The plot, while straight forward, is usually advanced via brief bits of poor dialogue and feels included almost as an afterthought because it's largely nonexistent. As a result you'll find yourself exploring many areas without a clue as to what you're doing.
You navigate Slimy through each stage by tapping anchor points. Touching a single anchor will cause Slimy to extend an arm to grab it, which will propel him forward. The majority of the game focuses on the banal objective of opening doors in a set pattern in order to advance.This quickly becomes aggravating because the entirety of the game is based upon this dull mechanic.
Slimy does boast a few powers to keep things somewhat fresh as you're scrambling for buttons and keys. He can slingshot his way into hard to reach areas when you hold down a shoulder button and then slide the stylus behind him before releasing. He can also swim when you stretch out an arm and rub it with the stylus to create a flipper effect. His most useful skill, however, is levitating, which you achieve by blowing into the mic; this gently lifts him upward and is useful for softening his landings, as well as cooling him off whenever he catches ablaze. Expect the game to test your lung capacity with this frequently used and exasperating feature.
The game's mundane levels are dotted with evil robots and pesky birds that will try to impede your progress. The majority of your foes can be defeated with a headbutt, though you can easily avoid them as progression usually does not require combat. Consequently, you'll spend more time avoiding pointy walls and collecting candy to restore Slimy's health than you will on the warpath. The ability to move the camera with the directional buttons is quite convenient for these tasks as well.
While swinging over lava pits and even tackling the game's only boss may sound like fun, any enjoyment you could possibly get out of Mister Slime is ruined by its poor level design, slow pace, and a slew of other annoying quirks. You can easily get stuck between objects or blown into corners by robots where you're forced to wait until you die, or, as in the latter case, a robot mercifully leaves you alone. The game's status ailments quickly become infuriating and add to the amount of time you're unable to move. For example, cleverly placed paralysis plants inevitably shock you, and if you're unlucky enough to be above one at the time, you can fall onto a plant where you'll be repeatedly paralyzed until you restart the stage or manage to get away.
Furthermore, you'll waste time in the ice world warming up Slimy's hands by rubbing them or waiting for him to completely defrost so you can move again. In the forest areas, you'll wait for spiders to spin a web around you in a pattern, eventually clearing the path ahead but blocking you in from behind. This tedious process is made more cumbersome by the weights you have to carry around to open doors triggered by sensitive pressure plates. Getting weights through doors can also be a hassle, especially when a door shuts behind you before you can get the arm holding the weight through the door. Occasional bugs will also slow your progress to a crawl. Sometimes you'll swing "outside" of a stage or get so tangled in webbing or stuck between objects that Slimy will flash out to a lovely black screen, so prepare for additional restarts. Thankfully, if you're really having issues, you can always set the difficulty to easy, which prevents you from dying and having to restart at the beginning of a stage, though the feature cannot mask the game's flaws.
If you're still interested in giving Mister Slime a shot, you'll find yourself left with only two other modes beside the primary adventure/storyline option: single level and multi-card play. In single level you can work on improving your completion time but only if you've collected all the flowers in that level and completed the game, making it mostly redundant. Multiplayer offers a mere three challenge types that are just as mundane as the game's adventure mode, including race, flower, and score. In race you'll compete against a friend to reach the exit of the same level, which can be quite irritating because you can only play together on the same level if both of you have already unlocked it in adventure mode. In flower mode, you eat as many flowers as you can within a time limit, while score is a simple matter of eating flowers and beating enemies for the most points. The game's only other bonus feature is the inclusion of secret areas that you unlock by collecting all the flowers within a level, but the game's level design flaws may very well scare off the avid flower collector.
Mister Slime looks about as simplistic as it plays, displaying gameplay on the bottom screen while relegating Slimy's health, points, and menu items to the top screen. Each of the five worlds is sufficiently distinguishable from the next, featuring the standard hot and cold areas along with a typical forest and a rather dull robot city. The backgrounds are colorful, and Slimy is as detailed as a green head with arms can be. You do also see a tiny bandage form on Slimy the more you keep throwing him into walls and bad guys. The music is of the peppy variety but feels like cheap MIDI compositions designed for last-generation handhelds. Ultimately, there are simply too many better, child-friendly games on the market to make Mister Slime worth the trouble.