Some levels when you can't build the castle are very hard to finish when you meet a wyvern and you just have balls of fire ...
or do you know a website with a full strategy guide ?

Cheats: Press "i" then type "quick" to activate, after that alt + function keys will do various things (destroy other players, castles, enemies, more mana etc).

The best way to defeat the wyverns is just to avoid them until you have better spells, or lure them away from your castle and let them kill you. After you regenerate they will usually leave you alone for a while.

Many Thanks, Samatar.
I can pass the level I was stuck in.
I saw cheats which said type ratty or quicky, and yes it didn't work

By the way, I'm not satisfied because I'm long from the 100% of the level.
I'm in the labyrinth where you change rooms through the mirrors.
You start with the spells Magic eyes, fireball, Mana Catcher, Castle & Shield
But no room enough to build the Castle.
I can get through the levels escaping giant crabs and get the spells of healing and weapon reflect but still dying when meeting the wyvern.
There is a spell over a wall where I can't climb, so I can't get that spell.
I pass through the mirrors but turning in round in the same rooms again & again.
Do someone have a tip for me ?

I found the way to do on youtube :
http://www.youtube.com/watch?v=aSkcJvVSG5k&feature=related
http://www.youtube.com/watch?v=nw5V70qux7A
Thank you

I think I only managed to pass that one because someof the enemies blew a hole in the out wall that I could fly out through and build a castle. I was never able to get to that spell you refer to without cheating; my guess is that some event is supposed to trigger another teleporter but I was never able to figure out how.