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.