I made a full mage play-through of this campaign, and it was rather enjoyable. There is so much potential in this engine if it's developed further.
I have compiled a rather long list of all ideas and feedback that I wrote throughout my play-through. I hope some of it will be useful.
FEEDBACK:
-Add an option to switch off "crit camera shake"; improve it with only a single "pulse" on crit instead of full-on shake.
-Keep recent areas in memory for 3 minutes or so. This means don't respawn enemies and despawn items.
-Add an overlay (or fullscreen minimap), as well as a world map.
-Add randomly spawning elite version of normal enemies that drop loot
-Add randomly spawning golden chests with better loot
-Improve boss chest loot to blues and purples. Too often boss chests drop nothing and it's really disappointing.
-Add multiple random affixes to loot - 1 for greens, 2 for blues, 3 for purples; to make loot more interesting and unique.
-Add item crafting - a way to upgrade white/green items by one level, adding an affix.
-Add a way to respec attribute and skill points to enable trying out new builds and skills without ruining your build.
-Add more sound variation and pitch shift.
-Aiming at enemies when they're walking around randomly is very frustrating. Increase hitbox sizes or make AI movement more predictable.
-Add more interesting AI behaviors - most enemies are either charging you down and/or throwing projectiles at you.
-Add more skills:
-dash skill with iframes in the ranged tree
more AOE spells
-immolate that burns nearby enemies and adds fire res - toggled, continuously drains mana, or health if mana is empty.
-chain lightning that jumps between enemies
-frost nova with short freeze (root) effect
-channeled arcane beam/life drain? spell dealing darkness damage
-Spell scaling is whacky - thunder strike deals less damage than shock for example.
-New weapon tiers make previous ones obsolete, even if it's a white quality one vs a blue/purple lower tier weapon.