Level 3

Level 3 URL: http://www.ouverture-facile.com/riddles/level3.htm

Clue: Go deeper in the reflexion [sic]

Click on the box that says 'mirror' in the bottom left hand corner. Move your mouse until it is over the mirror. You should see:

This should give you the idea of 'mirror writing'. Try 'level3' written in mirror writing:

http://www.ouverture-facile.com/riddles/3level.htm

However, this doesn't quite seem to work. The page is backwards, but you can't click on anything. The final solution uses the trick from level 2, to give:

Level 4 URL: http://www.ouverture-facile.com/riddles/4level.htm