How do you change difficulty? I didn't see that option in the option menu. I have no idea what difficulty I've been playing on all of this time.
You don't.
There is only one difficult: Cheese.
But seriously, the game is actually pretty simply.
Combine the spells and click.
If you get stuck in a part, just try using different spells.
Each enemy is weaker to some kind, so, using the same spell always doesn't works.
Also, you WILL die a lot of times that is part of the fun in the game.
if you play coop however, you can get revived by your friends, so the game becomes much easier
(you can get killed by them too, that WILL happen way too often, just kill them too to keep balance)
Also, don't play as yellow.
The yellow wizard always dies.