SubTerra is a freeware 2D action/puzzle game by independent developer Pieter Simoons (a.k.a Radiant) of Crystal Shard Games, in the style of classics like Boulderdash, Emerald Mine and Supaplex. You move a gnomish-looking character through a 'mine', usually a maze, but sometimes a more complex puzzle, collecting as many gems as you can. Sounds simple?

It's not. In the level 'Laser Maze', you have to figure out how to melt through an object with a laser, by arranging precious gems for the laser to bounce off of. Or carefully breaking open a wall to break into a gem vault, by killing 'skelwings' (skeletal flying creatures which explode at death) by dropping large rocks on them, in 'Sheer Heart Attack'.

One of the best features is the excellent built-in level editor. The editor includes absolutely everything the developer used to create the official 'SubTerra Prime' levels. Which are, by the way, very well done.

Mazes are the more common type of level (both in the official levels and fan-made ones). Level designers also often create surprisingly complex 'machines' (by using cloning tiles that clone objects, and movement tiles that move and rotate objects, and other object interactions) that players not only have to figure out, but often destroy, build or rebuild. Most often, both types are used at the same time, creating an interesting mix.

The only negative point I can think of is the lack of a real setting/plot, or theme. Technological devices such as explosives and cloning machines are mixed together with the fantasy-styled main character and enemies (firedrakes, phoenix-ish birds).

SubTerra is nonetheless one of, if not the best puzzle game ever, in my opinion. This is because, not just the versitility of uses of various objects, and good level designer but because the level designers and players play by the same rules. Objects react different ways depending on the situation (rocks, for instance, sink in water), but these cannot be changed to the needs of the level designer. The designers have to be just as clever in playing the game as players.

Whether you think it's the best or not, it's definately worth a try for any puzzle fan (or even non-puzzle fan, like me).