When you level up, Your Stats will be boosted up +7 and you get 100 Skill points per level to put into your abilities' levels. Max level for abilities is 1000, then change ability level to "Mastered"
HP is 100 + 60 x VIT.
Also, you start with only two Abilities, but the remaining abilities slots will be unlocked every 5th level up.
You gain Exp by defeating enemies. defeating stronger enemies grants you more exp on top of better loot.