SubTerra

SubTerra is a puzzle/action game, reminiscent of the classics Boulder Dash and Chip's Challenge, although SubTerra is more varied.

The basic goal of each level is simple: collect a set amount of gems, then run to the exit. However, a myriad of obstacles block your way, testing your reflexes, your puzzle skills, or both. There's falling rocks, duplication machines, enemies, laser beams, machinery that changes gems, heavy explosives, a variety of tools to help you out, and a monster that eats those tools.

To make things worse, each level has an additional "difficult" mode, requiring more gems, a harder-to-reach exit, and imposing a time limit. A nifty feature is that the tutorial levels, normally the easiest in the set, have a challenging extra puzzle in difficult mode.

Starting with a basic set of slightly over a hundred levels, SubTerra has since expanded with fan-made material to encompass more than 500 different puzzles. Players can use the in-built level editor to make their own, and join in the yearly Level Design Contest.