You need to find six keys to exit the room.
Key 1:
Look at the back door. When you see them close up, you’ll also find a key.
Key 2:
On the left side of the floor when you start.
Key 3:
In the lower left corner in the back, use the first white tile on the bottom row of the back wall.
Key 4:
On the right side wall, the sixth row from the bottom. You’ll see a faint key.
Key 5:
On the back wall, right of the door, use the sixth row of tiles from the bottom. At the top of the screen is a key.
Key 6:
On the back wall, right of the door, use the second row of tiles from the bottom. On the right is a key.
Look close at the door again and use the right key of the six to escape.
Game source: A copy of the game was found here on the internet.