Sub-Terra is a game I have never tried, and while I appreciate all games, I haven't had time to try this one. This general information is the best I can do for now. It has been borrowed from The Crystal Mine (Zeviz)

Gameplay Hints.

In-game Help

Always use the exellent in-game help. It contains descriptions of all items and answers to most of your question. To open help, press F2 key while playing.

General gameplay

Plan Ahead

When a level starts, the game is paused and you can scroll to see the entire level. Use this time to find the exits and make a general plan of action. In mazes it's often useful to trace the path from the exit back to source, instead of the other way around.

Use Pause

You will often be short on time, unless you are playing on easy difficulty in levels where time doesn't matter. To be able to finish a level within time limit, it's usually a good idea to pause the game (hit p key) whenever you stop to think. When the game is paused, you can scroll to see what awaits you beyong the edge of the screen, what is the state of machinery in other parts of the level, etc.

Look at Important Parts

Sometimes you need to push a button, a stone, or a switch to control events in other parts of the level. In this situations, you should be looking at the part of the level where the effects of your action will take place. To do this:

1. Pause the game.

2. Scroll to the area that you want to see.

3. Hold down F6 key and unpause the game.

The screen will not scroll as long as you are holding down F6.

Explosions

Don't forget that most obstacles can be removed by an explostion. Explosions can be set off either by dynamite, or by death of a monster.

Scelwings

Press F3 key to see the results of explosions of scelwings. These explosions often hold the key to winning a level.

Secret Rooms

Some levels, including all tutorials, have secret rooms. To find a secret room, look for anything unusual, such as some fire, or ice in the middle of a solid wall, or a scelwing that explodes into a teleporter.

Overcoming Obstacles

Enemies

Don't forget that enemies are very predictable. They always move in the way described in help. So it's easy to make them run in circles or lead them to their death. Some places to which you can lead the enemies: water, fire, traps, teleporters, glue, transports. You can also kill the enemies by dropping a stone, egg, or rolling sphere on them.

Munchkins

Never cross a munchkin unless you are absolutely, 100%, totally sertain that you do not need any of your current tools and will be able to find all the tools you need on the other side. Munchkins can be destroyed by an explosion, but sometimes you are supposed to save that dynamite for something else. Finally, try to pass munchkins before picking up any tools.

Secret Levels

To unlock the entrance to secret level you must fulfill the current gem quota. So it is obviously far easier to discover secret levels when playing in Easy mode. Entrance to secret levels looks like a flashing star imbeded in the brick wall. This means that secret entrances can only be found on levels that have brick walls.

Finally, there is 1 secret level per row. So if you've already found the secret for a given row, you don't have to keep looking for more.