It's arguably one of the key gaming experiences to indulge in some light puzzling on a handheld system. Whether it's Tetris or Picross, nothing makes a morning commute or quiet evening more relaxing than letting grey matter and opposable thumbs work together to solve a problem.

Pullblox / Pushmo is one Nintendo 3DS puzzler of choice. A simple premise of manipulating a structure to reach the top has served this series well for three games now - including an entry on Wii U - and this fourth arrival packages the various mechanics in those games for newbies, while adding new ideas to test the very best of push/pull-bloxers out there.

This entry takes a rather different approach, acting as a free-to-play game in the barest way possible. In fact, when you download Fullblox / Stretchmo you are given a mere handful of tutorial levels that offer a slight taste of what this game actually offers. To call the initial free offering a demo would be a far more accurate assessment - the main Fullblox experience must be paid for, with four purchasable packs offering the rest of the content in separate chunks, with the requisite discount for purchasing all four.

Fullblox's biggest gameplay addition comes in the ability to stretch objects. In Pullblox you pushed and pulled parts of a structure in order to make stairs to climb to the top. Its sequel was more about moving these blocks around and using gravity to place them in a fashion that would allow you to climb. Here, the puzzles are fully 3D objects that are no longer moved, but stretched in order to make the platforms you need. It is now possible to rotate the camera around the entire structure, and the added dimension adds quite a difference dynamic to the series.

In a way, it makes some of the puzzles a little easier in that you can give yourself a lot more surface space in which to manipulate the various blocks. However, the flipside is that you now have four sides of a structure to worry about, making it quite easy to get lost in some of the more complicated puzzles - but that's part of the fun, right?

As for the downloadable packs themselves, they all add something to the table - from the 100-puzzle Mallo's Playtime Plaza, which is the ideal introduction to new players; to Papa Blox's NES Expo, which is 50 levels of nostalgia-based sprite structures which were the highlight of previous games' offerings (and are some of the hardest in the game). If you're going to get one pack, we'd argue you might as well get all of them, as they're all enjoyable and offer slightly different experiences - as example is Corin's Fortress of Fun, which adds enemies that can both help and hinder your progress. Buying all packs is in the same ball-park of price as the previous one-off games, in any case.

A returning feature is the Studio, which is unlocked by purchasing any of the packs. Here, you can make your own puzzles in both the old 2D style or new 3D mode, share them with the world via QR Codes, or download puzzles made by other folks by viewing their QR Codes. As you can imagine, this leads to a potentially limitless number of puzzles to be played, and finishing levels in the purchasable packs unlocks new items you can use to build your own puzzles.