Zombie World (Free) by LEMICO Soft is a puzzle game where you are presented with evil-looking sunflowers that seem intent on raising the dead. You have to help connect them to all the tombstones on the map by means of a network of pipes.
Naturally, the pipes start off in a state of disarray. The pipe sections can’t be moved from where they’re found. Instead, you can rotate them clockwise with a tap.
Pipes can also be connected across the edges of the screen, similar to how Pac-Man can move through the edge of a screen to reach the other side.
Every tombstone must be connected to a flower to complete the level and unlock the next level.
Unfortunately, no option is given to pick individual levels so replayability is limited.
When you tap the option to buy the full version, you’re given the option to instead buy Gas Tycoon 2, which has all the same puzzles, but with a different skin.
Zombie World is a lot of fun since it takes some effort to solve the puzzles. It would have been better if levels could have been selected randomly and if upgrading the game was for the one you’re actually playing.