The Agar.io map is an interesting concept. It may very well be the first map of its kind to show up in Minecraft. Unlike most maps which are your typical Minecraft fare with an occasional town or quest, Agar.io is highly reminiscent of the old Snake game on early computers. From an overhead view, you will guide your player (who is riding a slime block) as you try to go around a board, grabbing up good things to eat while avoiding a number of hazards. Some of these will just bump you around but others will actually kill you, so there is a difficult curve to learn here.
The most confusing part will probably be figuring out the new perspective, which isn’t really native to any other Minecraft maps available right now. Once you figure out how to move around in the new setup though, you’ll already be halfway to having the Agar.io map mastered. It’s really a very interesting map and kind of hard to explain because there aren’t any other Minecraft maps that relate to it. The best thing you could do is download this and try it for yourself to see what it’s like personally. Just be sure you’re using Minecraft 1.8 or up when you do.