Your spell type is based on which weapon you're using, meaning it's easy to put points in the wrong tree. You are not told about this in the beginning. Switching to a different weapon later will cost you a souls. Refunding skill points costs even more souls. The cost gets higher the higher your level is. You'll notice a lot of things cost souls, which you acrue at a snail's pace.
The difficulty is not based on how many gates you break, but on how many enemies you've killed. You can get quickly overhwelmed by enemies that may as well be invincible as soon as the first area for using one spell. Bats and are too quick to be hit by most weapons. There's also no limit to how many times they can hit you in a period of time, meaning they can drain your entire health bar in literally a second.
It's like you had a good action game, and then went out of your way to make anything and everything about it as needlessly frustrating as possible.
 "mini Tower Defence (mTD)"){kind=icon}
 "Zombie And Juliet"){kind=icon}