Bring back passwords :p
I miss them and they were fun.
There were, hunderds!
Also:
Every 5 or 10 tower level should come with a password that's gated. You only see the password when you pass the tower level, like every ten. The prize could be anything. Maybe a joke. Maybe a rubber chicken.
And it won't work unless you have the tower level so no worries about monkeying up things for newer players 8)
