Mekorama is a worthy addition to the puzzle-game genre, with pretty mechanical puzzles and an adorable robot that players are charged with getting from Point A to Point B. Players can move the robot through its mazes by tapping on accessible squares. But it’s not always a clear path to the end point.

Players must drag movable parts of the levels to clear obstacles or plug gaps in the landscape that might keep the little droid from reaching the finish line. This free game comes with 50 levels — and plenty of mental exercise.

The developer regularly posts new levels on Facebook and Twitter that can be downloaded. Users can build their own levels and share them, using a Minecraft-like system that lets you create your levels block by block.

There are in-app purchases to get hints, but it’s generally a pay-what-you-like system. The app will also ask you in certain circumstances to throw a little money (a buck or two) the developer’s way. It’s a small price to pay for the enjoyment. Free, for iOS and Android devices.