I read in the comments old version liked to forget the saves, but never happened to me.
Heck, I was messing around, and the save must be somewhere on the computer, not online, because an other site showed the same savefile from AG.
lvl19-20: much easier than the blue level was. My setup for these levels are working setup: start with a whale or two, than summon 2 boar for emergency-cover and some damage between Darkdog's hits, than just replenish the Water Totems.
lvl 21: chickens attack only this distance: C X X E, so at best you can put two chicken behind a boar. But this is the same distance a whale works, and you need to heal your boar, so make it W C B E. Before the Boar, under the feet of the enemy, put flaming spot. This'll last for a long time if you replenish the boar (seems the chicken never expires, and the whale will last until your line crumbles). Than make a new setup one floor above.
Likely I did not mention, but this being hell diff and all, my jewelry is one food replenish and one mana replenish.
Some swords I tried:
Soul Scythe: the equivalent of food mace, but this is a terrible version.
Dimensional hammer: told to randomly teleport monsters. If that "randomly" would be behind you, that'd be good. But it is not. And it is way more expensive than trying your luck.
Wind rapier: finally a projectile-sword. The shot goes through all enemies present on the whole field as all projectiles in the game (think on Fist Mace).
Ice Sword is way too expensive compared to what it does (this is practically the freeze mace, but a much worse version, while even the original was not so good).
lvl 18: this was the point I no longer felt able to go with my default level weapon. I either needed a couple of levels with skills like "'add this to the currently equipped weapon" and "aura damages enemies", or a better quality default weapon. So I farmed the first boss for it, and finaly got lucky at lvl 18,and a lvl 5 one I got, the best quality item it seems falling there.
Not much problem after that. The Witch can't turn the protagonist into frog. The problem is the number of units, and that too for only the healing of the whale(s), so start summoning some boars AFTER you eliminated the Cave-wave (else they might be slaughtered).
Occasionally some miner zombie comes, and hugh groups when you battle the Witch herself so you should preserve mana for using the knockback-sword (or whatever you have/brought/prefer). But otherwise very doable. If you have the weapon.
PS: Darkdog's survival-mode is unlocked now. Paladog's survival mode was open as default.
Unfortunately it seems here the highest item is again lvl 5, so farming for jewelry if have to will again be at the first boss (lvl 3 manareg + lvl 1 foodreg is my best).