Google FooBar Challenge

Hi all,

Yesterday while I was querying some Pythonic stuff, this came up :

I know, I know, that's a pretty lame query. I just never did passing by reference in Python before. Anyway, I accepted the challenge, only to found out that it's the legendary Google FooBar Challenge!

Note : I was told not to share the challenge problems. Sorry for that, but I can share the interface with you.

This is the shell, and it looks cooler than mine!

After I solved one challenge, this is what I got :

The bunny is actually hoping around! Too bad I couldn't record it.

As a competitive programmer for some years, I find the first few challenges pretty easy. As you can see, I solved the second challenge in less than 7 mins. I could have solve it faster, but the system fails to receive my submission and I spammed quite some time.

I gave the link to one of my friend, so it should not work anymore :(

Have you receive an invitation before? How was the experience? What is the highest level you managed to got?