[[caption-width-right:300:Mazes, gems, and keys]]
''[=SubTerra=]'' is a puzzle game by Creator/CrystalShard and can be downloaded [[http://www.crystalshard.net/subterra.htm here.]] Not to be confused with a film ''Subterra'' or with a game ''[[VideoGame/{{Touhou}} Subterranean Animism]]''.

The game's main objective is to get gems and then reach the exit, while any number of lethal obstacles get in your way, such as falling rocks, dragons, explosions, fire and water, and floating skulls. The obstacles include the gems themselves, as a gem falling on your head will kill you. Depending on the level, you need to use careful planning, quick reflexes, or both. The game incorporates many elements from VideoGame/BoulderDash, VideoGame/ChipsChallenge, VideoGame/{{Sokoban}}, and VideoGame/LaserLight.

There is also a second difficulty level, which requires you to get ''more'' gems in a level, reach a special and usually harder-to-reach exit, and imposes a time limit. In a nice twist, all tutorial levels have a secret room with a pretty difficult puzzle, which is required to solve the ''tutorial'' on hard mode. The original game contains 108 levels in the Prime level set; a level editor and yearly level design contest ensure that there are many more out there.

A sequel exists, which contains several other kinds of objects, as well as a nemesis monster.

!!This game provides examples of:

* BlockPuzzle - some levels borrow from VideoGame/{{Sokoban}}, and various obstacles can be defeated through pushing in the right block. Ice melts fire, cushions float on water, and so forth.
* CollisionDamage - touching an enemy kills you. Being adjacent to an enemy will kill you, unless you have the shield powerup.
* ControlRoomPuzzle - several switches affect distant parts of the level; in some of them you are locked in a control room and have to solve the puzzle indirectly.
* CoolGate - teleporters.
* EverythingTryingToKillYou
* ExcusePlot - the "plot" intentionally has absolutely nothing to do with the game.
** FridgeLogic - why were the traps left ''by the miners themselves?!'' Chalk it up to ExcusePlot.
* ExpansionPack - once a year, featuring levels from the level design contests
* ExtremeOmnivore - the dragons, who will cheerfully eat rocks to get them out of your way. Of course, they will also eat ''you'', given the chance.
* FakeDifficulty - averted, in that the game intentionally does not contain invisible walls or secret passages.
** Played straight in the fourth secret level -- yes, the random shifting walls look [[RuleOfCool really awesome]] and it's a clever gimmick... but due to the random nature of said level, there's no reliable way to beat it on hard mode before the time runs out. Really just a LuckBasedMission, but the odds of the time running out before you finish the level are ''heavily'' against you.
* FrictionlessIce
* HyperDestructiveBouncingBall - one of the objects.
* InterchangeableAntimatterKeys
* KillItWithFire - most things that kill you will also kill enemies.
* LevelEditor
* LightAndMirrorsPuzzle - an explosion that catches a certain gem (the ruby) can create a laser which turns left when it hits a diamond, and right when it hits an emerald.
* LockAndKeyPuzzle
* MeaningfulName - many level names
* MookMaker - the cloners in the first game, the wizard in the second.
* MoonLogicPuzzle - From the PRIME set, "Euler" if you're playing on hard. The solution it requires is actually very simple and it's logical... but it's not natural for the game and there are NO hints for it - you have to figure out the "trick" yourself. Thankfully, it at least makes sense afterward, avoiding GuideDangIt.
** To some extent, the secret rooms in the tutorial levels.
*** Averted with the secret levels. You can't miss the first one and when you find it, you will be able to search for the others yourself as the game has just taught you the mechanic it uses for hiding them.
* NintendoHard - several of the later levels are this, most notably Rooms Of Confusion and Razzle Dazzle.
** On some levels, the low time limit counts as well, if you're playing on hard mode.
* NoFairCheating - various cheat codes exist, but completing a level with them simply doesn't count. The exception is the level warp cheat.
* OneHitPointWonder
* PressurePlate - switches can be triggered by walking over them, but also respond to rocks, enemies, and so forth.
* RubeGoldbergDevice - many levels involve this. Some are deceptively simple.
* SecretLevel - the PRIME set has six of them.
* SelectiveGravity - rocks and gems fall, most other things don't. This is common to the DiggingGame genre.
* ShoutOut - many level names.
* SpiritualSuccessor - to {{Supaplex}}; it even got the greenlight from the authors of Supaplex, and includes several of the levels from that game.
* SprintShoes
* StuffBlowingUp - oh so very much.
* SuperDrowningSkills - unless you have flippers, which allow you to cross safely.
* TheMaze - only a few levels are really about pathfinding.
* TimedMission - ''every single level'' if you play on hard. If you play on easy, the time limit is just for bonus points.