All the answers here! The main goal in 100 Doors is to escape the room.  Using all the possibilities of the device you need to open each of 100 doors and move the doors to the next Level.
Search for hidden objects, solve puzzles and use an items to do this!

Level 3:

There is a tool hidden behind the picture. Tap the picture to make the tool fall on the ground.

Grab the tool.

Tap the key on the ground. The teeth of the key is the solution.

Select the tool in your toolbar and tap the door knob.

You need to reproduce the design of the key. Tap the cylinders this way:

1 2 0 1 2

Middle, Down, Up, Middle, Down

Click here to go back to all the levels