A tridimensional Tetris set in a... tube!
Tubis is a tridimensional Tetris like game, in fact it is a Tetris game, only that you sort of look at it not from a cutout, but from the bottom of the pit. It's like the original game took the camera and mounted it at the bottom of a well. But, nonetheless, your priorities and requirements are the same: stack the tetrominoes so as to avoid unwanted spaces, so as to create a full array so that the continuous blocks will stack on top of one another. Therefore, Tubis is a bit trickier, since you have to consider the new dimension aspect, but, in truth, the same kind of mindset will be used. Graphically, to aid you with the new dimension, the game presents you the walls of the well with paper graph like gradations, so you can better approximate your positioning, a nice touch from the developers. Other than that the game looks alright, a faux 3D that works and that allows you to get the job done. Granted, it's a game that is a bit more difficult than your average Tetris game but, nonetheless the added difficulty will be welcome by players looking for a new version of Tetris that is about a twist of gameplay rather than a graphical addition.
