Boo! is a Halloween-themed puzzle game where you decorate pumpkins using cauldrons of coloured paint. The twist is that to create each design, you need to cover up different parts of the pumpkin using an assortment of items. The challenge is to apply the layers of paint in the correct order using the masking of each item to create the target design. It's unique and simple to grasp but takes a great deal of thought and experimentation to achieve each design.

In each level, you are given a pumpkin design to copy, 5 vats of paint and a range of items. By putting on eye patches, masks and hats, you can control which bits of the pumpkin are doused in each paint application, allowing you to create intricate designs.

There are 16 levels on the web browser version, and 21 on the mobile versions, each level being more challenging than the ones before it. You need to carefully think about the best order to do each coat of paint, and decide which items you need to put on your pumpkin each time. Mastering the game will take some time.

It's a novel concept, that results in surprisingly difficult challenges that forces you to think carefully about each and every move you make and rewards patience, persistence and planning.