Is level 20 is the last level? #2
Description
Brief answer: I do not know.
I just wanted to say that some levels (for example: level 11) include this sentence:
This is your own online hacker simulation. With over 20 levels that require different skills to get to another step of the game
Which may give a hint that there are more levels.
Another thing is, following Enter link in the last stage of level 20 sent me directly to the secret code. There was no need to edit the header using browser nor wget. Maybe it was a bug in the level at the time you wrote this solution.