flies and bats only drop health potions if they do drop one

Fire elementals only drop fire pots. Cold elementals only drop cold pots.

If you find a str 12 weapon but only have 11 str…
Without going into cursed items, a +1 weapon would in fact only require 11 str. Don’t wanna spend a scroll to identify it, just equip it (hopefully it isn’t cursed). If your can still surprise attack, then you have enough str for it, which means it’s at least +1.

Similarly if you wear an unidentified leather armor with only str 11, if you can still outrun normal speed enemies, it’s at least a +1 armor because you have the required str for it

Got 3 scrolls at level 4? They’re probably upgrade scrolls. There’s 3 inbetween every boss.
The vendor always has at least one scroll of magic mapping.
And (maybe?) always at least one remove curse.

These wells heal you to full, satiate all hunger and uncurses all cursed items currently worn.
If that doesn’t help you at that time, you can come back later. They can also be used to just fill your dew vial by throwing it in. Same goes for blessing an ankh.

Don’t know the official name, but its nice to have feather fall spell on hand to avoid the fall damage. Making father fall early on, you’re almost guaranteed to need it eventually.

Telekinesis spell to get the keys. Use haste (or the yellow seed) before the levitation potion if needed.
If you’re gonna run out of levitation, popping the feather fall can be nice to avoid the damage

you can examine crystal chests to have a hint if it’s a ring or an artefact. Choose whichever. But at least you have some control over what you get.

Goo
Fight it near water so you can remove the caustic condition. Hit it, move, hit it, etc. You should never get caught by its splash damage if you always move away using a corner.

Tengu
The guy will teleport around, don’t step on the traps. If the path through traps is too bad, use a ranged weapon until he jumps and resets the traps. Even when he jumps around, conditions like burning are still draining his health. Fire potions or wand of fire is nice. Avoid using stuff that fills the whole room like poison clouds as it’ll get you too.
The amount of traps in the first phase can probably get the scrying artefact almost fully upgraded.

Robot
If you have spare honeypots, now is the time.
The boss won’t spawn until you see one of the pilons that give them invincibility during the fight. Peek in without going too far, throw a honeypot where the pilon would be. You likely won’t have enough honeypots for all 4 pilons that’s fine. Choose the pilons that are harder to get to like one behind a pool of (soon to be electrified) water.
The point is to spawn a bee that will attack the pilons that provide invincibility to the boss for you. (If it turns out to be using that one specific pilon, but even if it’s not that pilon, at least you know you don’t have to check that one and limit the time you spend looking for the right one)

Undead king
Idk just hit the mobs, try and hide from the ranged ones. The animation next to the spawn point represents what will spawn there. The black smoke one are the ranged ones.

Attack the eye.
Move to avoid lasers, kill the little grubs so you don’t get overwhelmed. Go away when the fists spawn, their invincible on the platform. Read their description, pop potions for the elemental ones.