After losing twice during my first attempts, I finally got a lucky run and managed to start with the Giant Effin' Sword.
The run ended spectacularly by rolling a natural 20 with a EMO Grenade, on an enemy only vulnerable to fire, that had just ambushed me on the previous encounter.
I don't think it can get any better than this.
The only comment I have is about the run duration. I felt that 15 encounters was a bit too long. I'll probably try to shorten it the next time.
Overall, had a great time with it and can't wait to try it again.