You need to get out of that room.
On the wall is a MIRROR. Grab it from there. Use the mirror on the button of the middle window to reflect the beam and unlock the chest. Open the chest and use it to get a COIN out. Put the coin in the coin slot of the vending machine and push the button of the vending machine to let it drop something. Use the slot at the bottom of the machine to realize you can’t reach the drink.
Push the red button of the machine at the lower left to make the bar that’s on top soft. Take the soft POLE from the machine. Push the button below the window on the right and a huge weight will drop, killing you (this will be the only one, promise!)
On top of the weight is a HOOK. Take it from the weight and in your inventory attach the hook to the pole. Use the combination on the bottom slot of the vending machine and you’ll get some HARD CLAY out. Put the hard clay on the hole of the machine at the lower left and push the red button to soften the clay. Grab the SOFT CLAY and use it in the key hole of the door.
Now that the clay has the right shape, retrieve the MOULDED CLAY again and put it back in the hole of the machine on the lower left. Push the red button of the machine to harden the clay. Grab the HARDENED CLAY from the machine and put it back in the keyhole of the door.
Game source: A copy of the game was found here on the internet.