Ill give you a tip, you can bypass it completely, in room 2 (First room you encounter enemys) there is a mana upgrade and health, if you get those there's a switch on the wall that removed the gates at the end of room 2 section, this will give you 4 extra lives and a potion of invincibility, if you use the potion of invincibility for the circular trap area then you can bypass it completely, just hit the switch after it (This is a must) before the potion runs out, then you wont have to redo it all over again, there is a check point after that part btw
It is not possible to get there with a Priest btw, he has too little HP and will die at the very edge of the vortex.
Anyway, I must say that I've been really enjoying this campaign. It is very hard, but in a good way. I reached the boss with 0 lives, so I just couldn't finish it and started over with the double lives crutch.
I absolutely love the mapping, there's so much decoration and mood going on, really nicely done!
I really would appreciate some way for the Priest to get at the other side of the vortex though.. I always play as the Priest, and it's not exactly great to not be able to make it there since I only have 30 HP. I technically could return later when I have a bit more HP but that defeats the whole purpose of that secret...