Anyone who has played lately realizes spit has completely given way to magic missle as the new cheap spell. Missle is cheaper than shield, so unlike spit you wont be at a disadvantage if they reflect it. It also has two damage options with the charge, which i think is very powerful. To rebalance spit, i think it needs a boost. Maybe give it a charge option too, where it does more damage or moves faster. Or just increase its speed in general. I just dont see how spit is viable anymore as it is now.
Regarding the other spells, the demi spell just seems too pricy considering it can really only be used for the first hit with any efficiency at all. Think of it this way. It cost same as lightning, but is slow and easily reflected. Lightning meanwhile can be used to bait, hit under shields, and does more damage than demi after any second hit.
Dragon breath feels very balanced since it is very limited where you can use it. Its also a very exciting spell to play and you can take big risks being very aggressive with it.
Oxymora i dont have too much of an opinion on. Maybe it could cost a little more? I dont know that half the cost of demon is totally fair since it does almost the same thing annd has healing ability. Love the spell though, super interesting how it can heal your opponent if you arent careful.
Blood bolt seems good where its at. A pretty risky spell that also can be used aggressively and makes the game more interesting. Ive both been killed by an opponent with it and killed myself using it.
Curse is the bomb diggity. Really shakes up the game and seems pretty balanced for now. My only complaint is i think it should turn oxymoras heal to damage. It cost 40 mana, so it needs to do more than deny a pickup. Temporarily. Also, if it only works on pickups then it is useless the last minute.