Nice challenging game!
I have 2 problems though:
1. I can't see exactly what's the damage of the DoT, to do some math and decide when it's not worth to dispel it anymore
2. The keybind is particularly bad for me; I often use S when it's not needed, wasting mana. If it's not possible to rebind the keys, it might be better to put them all on the same row of the keyboard
But well done, overall. Not sure you still read this comment, after 6 years :)