I've gotten to demon halls a handful of times, but always died in the first few floors. This is my first time making it as Sniper (or Huntress at all, actually).
I have a +6 Grim crossbow, a projecting spirit bow, a ring of arcana, a +2 ring of haste, and +1 plate armour of swiftness. I also have a horn of plenty which I intend to transmute, and rings of tenacity, might, and evasion which I plan to sell.
Which crown upgrade do I want? I'm not sure which one plays best for this build. Does anyone have any other advice for not dying in the Halls?
Update: Yog is dead. Thank you so much for the help! I went Hawk and dumped the rest of my scrolls into Haste for maximum kiting.
I'm a big fan of the hawk. With speed upgrades it can more than keep up with your RoH, you can use it to see into rooms without having to expose yourself, at which point that projecting+arcana can do some fine work
I always go with Nature's Power. Having extra speed and bow fire rate can be very helpful, especially when you miss with your missile weapon and you can't recover it right away.
By the time you reach the halls, you should have Magic Map identified and have at least 4 scrolls for each level. Once you enter each one, pop a scroll and beeline for the demon spawner. Taking them out will make the fight against the final boss easier and clearing the levels before that less annoying.
Consider using a potion of mind vision followed by a scroll of lullaby after you've used magic map. Putting a level to sleep makes clearing it a breeze. You may want to use mind vision and a scroll of retribution for really annoying situations you don't want to deal with like a bunch of scorpions. Retribution is more effective if you're low(preferably less than a third) on health.
Light isn't too important on level 21 but you'll generally want to have a torch up at most times to avoid getting surprise attacked.
Having enough armor makes the game much more manageable. It's a good idea to have +7 or +8 scale or plate armor before fighting DM-300. You can beat the game with +1 plate armor but it's not recommended for newer players.
Be wary when running around with less than half health in the halls. Mobs there can easily chunk your health so you may want to top up with healing earlier than you would at higher levels.
Hawk can blind and cripple enemies. It also can dodge the first 8 attacks made against it.
This is amazing in the Halls for fighting Scorpios and Evil Eyes. The hawk can outright kill a Scorpio because Scorpios don't attack in melee range, so the hawk closes the gap while dodging everything, then cripples the Scorpio and hits it with melee. Also, you can catch up and melee it or hit it with ranged weapons.
Same with Evil Eyes. It blinds them so they can't zap you. They will eventually zap the hawk when it runs out of free dodges, but I have hawks last until it naturally time-out many times, scouting and crippling things.
It can take a little bit of micromanagement to use well, but it's really not bad.