I bought all the summon skills first and some summon gear. Then the game was cake - I just summoned the mage things and guarded in front of them. Final boss didn't even scratch me lol.
I really liked this and beat it easily on Normal difficulty. I see that others are complaining about the gameplay however I actually thought that the spells and special abilities offered a lot of variety and I enjoyed playing through the whole thing. Oh and the spoofs on the various fantasy games were humorous :P. 5/5