Quoting Nintendo Life's review of Fallblox:
"Meet Fallblox – a game so clever that its very title could be a brand new synonym for “mindboggling”. Predecessor Pullblox / Pushmo remains one of the best titles on the 3DS eShop, an extremely smart puzzler that's fantastic value for money. Fallblox, known in North America as Crashmo, is no lazy sequel: it takes Pullblox's basis, tips in entirely new mechanics and completely outdoes its older sibling in the process. And if you thought Pullblox was tough, you ain't seen nothing yet.
Fallblox's setup is very similar to the previous game. Each puzzle is set on a grid, and you've got to arrange a series of coloured blocks of various shapes and sizes, from single squares to gigantic slabs and all sorts of complicated styles in between, in order to make a path to the goal – usually the peak of the tallest structure. This time adorable puppy-cum-sumo wrestler Mallo has accidentally released a bunch of pet birds, each of which has conveniently perched atop a puzzle ready for you to grab."