Grimrock

You need mine keys.
On that level are several so you should know how a mine key looks and be able to build that with the blocks.

The one where you have to push four pressure plates via a teleporter in front of you.

There are 5 pressure plates (3 in the top row, 2 in the lower row).
First activate the additional teleporter and then the door, walk backwards until you hit the door and throw something through the teleporter (from west) before the door closes.

Deactivate the additional teleporter and again throw something through the teleporter from west (this has to be second step as the additional teleporter would reset the plate underneath it).

For the topplates throw something through the teleporter from south from varying distances to hit the three plates.

There's nothing behind the gates you absolutely need, just several goodies.