if you are at level 10 already you don't need to dual anymore if you don't want to.
please remember you raise your spell power much faster practising with Victoria in the case room.
Then once your spell power is above 220 on each spell and being at level 10 you can beat the Minotaur.
Nemo56 getting all 4 spells up to 220 is mad overkill. You really only need to level up the basic Combat Bolt and one of the two attack spells with a rider effect. I like the stun one, because an occasional free round is far more beneficial than an occasional burn damage effect. The thing is, all three of the spells other than the default attack share the same cooldown, making learning more than one of them a waste.
And on that note, the heal spell is a trap. You take a bunch of damage, you cast heal, then even if you heal more than you took, you're getting attacked again and going right back down to where you were or lower. If you ever find yourself in a situation where it would make sense to cast heal given the current mechanics, you've already lost. If they had all had different cooldowns then it might make sense to drop an occasional heal during the free round you get when the stun effect procs, but as it is you're best off to just avoid it.
Lastly, spend the cash to get the crystal that upgrades the combat bolt spell. If you click on its icon on the right hand side of the fight screen, and time your combat bolt spell right to hit at about 95% or so power, it will do double damage. Be warned, however, if you hit it at a lower percentage, you take the damage instead, which sucks.
I was able to beat the Minotaur with around 200 bolt power, 160 stun spell power, a bolt gem, and a pile of the reflect damage potions, which I used one of each round.
Of course, as always, ymmv.
