GBC, that isn't actually true.
However, things like "Press Up, Down, A, J and R in order to unlock god mode" is impossible.
On the other hand, you can do a
lot of things through scripting. Because you can alter the players health, you could make a God Mode (by making the script constantly add to the players health), but you'd need to think cleverly as to how you'd integrate it--the simplest thing would be to have a really hard-to-find object, and if you pick it up, the script triggers. You could have other things similar to this as well--just think creatively.
The script would be fairly simple to make, but I can't at the moment. Hopefully though, someone will come along and make something up for you.
Evil has a new name. Demo out now!