Use the following steps to complete the game

Click the bottom right corner.
Get the eye from the skull.
Get the rib.
Click the bottom left corner to return to the original screen.
Use the stick on the mushroom to get a sticky substance on the stick.
Combine the stick and the eye.
Go back to the mouse. Click on the mouse to hear the notes.

Use the stick on the ribs to match the notes.

First part
111
4
6

Second part
44
33
22
1

Watch the short intermission sequence, then get the scissors.
Go back to the original screen and use the scissors on the wall to escape.