Love this game. It's very well done and I enjoyed playing through it greatly. And the randomness makes it nice for replays. However, I did feel there were a few things that could be improved.
-Damage upgrades didn't feel like they had a real impact until I had all of them. It didn't help that I could never get a real feel for how much damage I was dealing with spells either. All I could tell was that EB did more damage and IS was rapidfire. I still used them all the time, but I could never solidly tell how much damage I was dealing past 1-hit kills.
-Plague Nova is the spell I felt was least useful and thus I used it least. The fact that it fires bullets at the area around me made it hard to aim and not really reliable; I felt lucky to hit even one enemy with it. Instead of being a burst of multiple projectiles, I'd suggest making it into a short-range pulse-wave style spell. That way, it would feel like a more defensive spell for when you're swarmed, and less like a spray-and-pray.
Beyond these two issues, I'd just love to see more. More levels, more enemies. Maybe even more companions beyond the pets, like Knight and Mage, who can only be unlocked by saving them or performing side-missions. Knight could stay near Marksman and melee anything that gets close, but he can only melee. Mage can cast powerful spells that do a lot of damage, yet she's very slow at casting. A Priest can 1-shot or 2-shot the undead and necros, yet those are the only enemies they can kill. A Rogue will attack humanoid foes from behind, jumping out from the edges of the map, yet they'll also take the money the mob drops. You can only have one companion with you at a time, they may even take the place of pets, each with their own dialog and remarks, showing their personality and/or relationship with Marksman, like Knight and Marksman butt heads and compete, while it's hinted that Marksman and Mage might have been more than friends. Plus, you have characters for a potential multiplayer version of the game as well.
I'll be looking forward for the next version of this game, and probably replaying this one a few times in between. Keep up the excellent work.