To beat any map you just need to place the Obyn Greenfoot Hero at a good space covering a large area. After that place up to 6 druids with 0-2-4 upgrades (and one with 0-2-5). The rest are just style points. You will beat almost any map with this strat. BUT until Obyn is on a high enough level to detect camo bloons you need a sniper or magic monkey to detect them. After that its basically free