We've already talked about how it compares to Nintendo's Captain Toad with the looks of something like Monument Valley but it's also its own thing thanks to a wide variety of puzzles and a neat level building tool that lets you quickly share your personal levels via QR codes.
Plenty of people have already shared levels via Twitter and you'll even find one hidden in the screenshots of the App's description.
You have to try it and you won't be able to find an excuse as the game's free to play with a "pay what you want' model. The game is absolutely free but asks you regularly if you want to buy an iAP to support its creator. How much you pay for the game is up to you.
Give it a try and then buy Martin's previous game, Odd Bot Out as it was also absolutely brilliant.