Welcome to the Monster Castle! All kinds of creatures are abroad there. At first glance they might look scary, but they have the best intentions: to protect the princess against hostile invaders. The skeleton (shortcut Q) attacks invaders from close, the plant (shortcut W) shoots spikes from a distance, the slime (shortcut E) slows down the enemy, the devil (shortcut R) transforms itself and stops the enemies for a while, the hive (shortcut R) sends hordes of bees to the enemies, the corpse (shortcut S) gets extra bones for each enemy killed, the mud man (shortcut D) fires mud balls at the intruders and the dragon (shortcut F) does the same, but with fire. You can also cast four different spells on the enemies: a sort of blaze (shortcut Z), a blizzard (shortcut X), thunder and lightning (shortcut C) and a tornado (shortcut U). When a monster has attacked a few times, you can upgrade it when a star appears above it. You can play in four castles, and in two different game modes: easy and normal.
Press one of the shortcuts, and then click there, where you want to place a monster or cast a spell.