I'm Level 7 Mage on Impossible. Second run at the game, after playing my Mage up to Level 18 on Normal and was about to finish the Dwarven Area's - that's when I found the game became way, WAY too easy: there was no real army that I felt "dread", I plowed through everything including all my Item's "Guardians" (Gremlin Tower fights) - even though I didn't have Phantom or Resurrection or Gate or Geyser - But I did have Sacrifice/Hypnosis and Inquisitors... Does a true Mage even needs more in this game?
My "crowning achievement" - defeating on my first encounter a Level 26 Demonic Hero I found running around down at the Dwarven complex... didn't even break a sweat.
On this second run, the first thing I did was Max out the Alchemist skill. Sounds suicidal, right? I mean... no other skills to speak of for the first few Levels...
But I made a tactical choice and I stood by it. So far? I am ecstatic by the results because I am "swamped" with Crystals and my Spell Book contains exactly all the spells I will ever need, want and most importantly: Use, at the best Levels I could get them.
(that is, all the spells I could get my hands on up to this point!)
Believe me when I say it is 10 time more fun to flip just 2 pages in your book looking for your spell of choice than to flip through 6... because let me tell you right now - 4 of them are not worth a second glance!