To complete the game, you have to collect four reptilian limbs and a valve, and then use them all over the main entrance in the room.

Scenes:

Starting scene: The scene you start in.
Bed scene: The scene with the stone statue in the bed.
Main entrance scene: The scene with a door full of golden sand.
Junkyard scene: The scene with old and broken machines.

Limb 1:

Open the lowermost drawer in the bed scene. (Lower left) Get the knife and turn right twice to the junkyard scene. Use the knife in the leftmost coin slot, and get the coin. Turn back to the bed scene, and put the coin in the piggy bank. (Middle left) Get the reptilian limb.

Limb 2:

Grab the floor brush in the lower left of the main entrance scene.
Pick up the transistor in the junkyard scene (on the floor between the two middle machines), and put it on top of the machine in the starting scene. Pull the lever, and wait for the “welcome” sound. Click on the screen and on both green switches to open up two buttons in the starting scene. (upper left) Push the right one of them.
Turn right to the bed scene, and enter the hole in the wall. Use the floor brush on the reptilian limb in the lower right, and click on it to pick it up.

Limb 3:

Push the red book lying on the other books on the bokkshelf in the starting scene. (Upper right) Get the note that falls out.
Zoom in on the chalk board on the left part of the starting scene, and use the note to get a 5-number code. The code changes every time you play.

Limb 4:

In the bed scene, push all red pillows once to reveal a key. Use it on the chest in the upper right of the main entrance scene to get a mahogny eye.
Push the left button in the upper left of the starting scene. (If you can’t push it because it has a cover on it, see “limb 2” to find out about how to open it.)
Turn left to the junkyard scene, and get the mahogny eye from the hole in the wall. Turn left to the main entrance scene.
Put both eyes in the strange statue in the upper left. Get the reptilian limb.
Valve:

In the bed scene, click the valve in the middle right part of the screen 4 times. Turn right, and get the valve from the floor.
Endgame:

Put all 4 limbs by the statue over the door in the main entrance scene. Put the valve in the hole over the door, and click on it to turn it.
Click on the hole in the ground to enter it. Continue going down, and drop down through the hole in the end.

Written by Questioner.