I played an evil run on my second play through. In act 3 I randomly walked into a fireworks shop and it didn't take long for me to realize what must be done. I managed to clear the building and scavenge every firework, loose or boxed, into my stash. After finishing up all my loose ends in act 3, I hauled as much as I could with the mighty cloth on my barbarian to the final fight.
After clearing the way to the portal, I gathered everyone I could inside the portal, laid down every explosive on hand and sent a lone little rocket to set it all off.
I want to say it looked amazing but my computer couldn't handle all the fireworks going off all at once and lagged hard. However, I did one-shot the Netherbrain on turn one and accomplished exactly what I wanted.
Spoiler
I collect ever explosive I find along the way. At this point it's more about "How much can the game engine and my PC handle...". Even got a bunch of hirelings and used the vendor reset on level up to really milk some of the vendors. (This is also a great way to get some of those nastier fights in honor mode completed too...)
Just to see what would happen, in one of my evil runs, Arabella dies and for some extra spicy evil, I brought her dead body to her parents and dropped it in front of them. To my surprise... they react.
One play through I went minion master. ALL THE MINIONS. Terrible idea... each turn takes 5 years and things get clogged up real quick.