Even with it though, Four Horsemen can be a little confusing at first. If you're confused, there's a helpful tutorial built right into Four Horsemen. You earn extra balls by filling a box entirely with one plague color, and that will keep you going as you level up and the game gets harder. Each ball you drop is one less you have to play with.
Keep an eye up at the top of your screen though.
Once you've managed to entirely fill one box with the same colored balls, you'll get your points and that box will reset. The object of the game is simple - just drop colored balls (called 'plagues' for game purposes!) onto one of four squares to connect balls of similar colors. Once Pokki has been installed, you can run Four Horsemen in a matter of seconds.