Got Gonzales done as the pyromancer (which speeds up the early battles). Game completed in 29 minutes and 30s - I used a shortcut level with the seed command and it took a few attempts, and I did the last two boss battles with zero health and some gamble scrolls.
Shortcut achievement still isn't complete as I had to gamble the dragon master, which I think stops you getting that achievement. Ah well - I guess I'll probably use the same seed again but take a less aggressive/high speed approach.
EDIT: Re-did exactly the same level/tactics, but slower and more thoroughly and did the boss fight properly, and Shortcut is now done as well
Three to go...
EDIT: And that's Friends To The End done as well. Impressively, I got as far as the achievement without the boar dying and having to be resurrected at any point - I was the chanter and had some very high-damage orbs being fired, and a turret staff. I eventually found the life staff, but only on the ice level - of course I also had my strawberry staff & was feeding the boar a lot. I decided to finish the game, and the boar did die once in the desert boss fight - I got the elephant, and it's basically impossible to avoid being knocked off your mount with its ridiculous super meteor strike attack thingy (I think the elephant is probably the game's hardest boss? I'd definitely say it's harder than dragon master: the ice level snowman is probably the second worst after it I think).
EDIT: And that's all of them done, the last two were pretty simple.