Level 11. A triangle and 90 degrees above the door. You have to count how many 90 degree angles there are in each of the shapes. The exit code is then 4213.
Level 12 of 100 Doors 2013. Above the door is 783. Tilt our Android phone to the left and get the rock. Use the rock to break the glass box. You will see a number 4 behind the glass. The exit code is 7834.
Level 13. Pick up the lego ice tray on the floor. Fill it with water using the faucet/tap on the wall. Select the filled ice tray in your inventory and tap on the <0 wall button. This will open the door.
Level 14. This is a simple swipe level solution, these doors are not very difficult this far. Swipe the left up and the right down to exit.
Level 15 walkthrough for 100 Doors 2013 on Android. Press the buttons from top to bottom while following the lines shown. Start with the left side from top to bottom. Then do the right side from top to bottom.
Level 16. When you shake your Android device you will get a key. Use this key from your inventory to exit the floor.
Level 17. Tap on the top row to get a can. Pick this can from your inventory and tap the bow on the right. Continue using the can on the other bowls in order to make the snake go all the way. You will see a code on the snake: 7911.
Level 18. Place a finger on each white circle. Swipe up with both fingers at the same time. An easy door to open.
Level 19. On the floor tiles you will see a pattern. Copy this pattern using the black balls in the room.
Level 20. You will see a code 1368 above the door. Use the two black arrows you see to enter this code using the circle. The door will then open.