I just beat v 17.0. Spoiler filled description of victory and comments below:
It was really fun. I was playing a war vet, which I think is by far the easiest class. Even late game. In theory the cultist should be the best late game because he has lots of spells, but I find the cultist is always rather squishy, and magic is much less potent once you find late game guns.
Lately I've been using the sawed off instead of the punp shotgun, and I think its part of the reason I won. Its not so much that you get more damage per ammo, and far more that you get more damage per turn. After I fire two shots I switch to a different gun, but beginning every combat by obliterating several enemies makes fights way easier. Of course, late game shotguns are useless anyway.
Another thing that helped me win was finding lots of dynamite. I don't know how much dynamite I had, but I always seemed to have enough. I've had many character die because they ran out of dynamite (particularly cultists who don't start with any). But this game I had plenty. Late game I even had enough dynamite to kill a hunting horror that cornered me. (I hit it with dynamite one stick at a time as it chased me. It took 4 to take the thing down. )
On that note, mobile is the absolute most important feat in the game. Without it the game is simply impossible. It lets you avoid tough and impossible fights, helps you conserve resources, and allows you to kite melee enemies.
But of all the things that helped me, the thing that helped me most of all, and really allowed me to win, was finding two rejuvinator devices, both at fine quality. I only ever used one of them, but having two made me feel confident to make the decision to use the rejuvinator device early and often. I never actually found any potions of vitality, but rejuvinator devices are like having a big stack of potions of vitality. Those two items alone would have made this my luckiest game ever.
But I also found a staff of the pharoah king in the late game. In addition to being a great melee weapon, a summon spell is excellent for the war veteran which normally has no use for spirit. I barely ever used the spell though, because I was so afraid of hostile mummies.
The late game was really fun, except the very late dungeon was filled with hunting horrors which are essentially impossible to fight. I only killed one, and ran from the rest(twice I used potion of descent to escape, and it would have been three times if I could descent from floor 29.) This is the main reason mobile is absolutely essential BTW. Imperceptible doesn't hurt either, and often gives a turn or two head start.
The actual final boss was easy compared to the never ending swarms of hunting horrors, and I happily took my second win. I suggest he be given some minions (although hunting horror minions would probably make him too hard. Or maybe just leave him how he is, a mild final boss fight isn't necessarily a bad thing.
One day I hope to win without getting massively lucky. Or at least with something other than a war vet.