So I've been messing about with this challenge and figuring out what's what. So far here are my findings.
I've actually found that mirroring my attack controls to make use of the tear convergence point behind me helps a lot when starting a room. After getting enough tears going, moving around a lot makes my defensive orbit more unpredictable but more effective in dealing with enemies.
Swarms of flies are much less of an issue. You can usually devastate them pretty easily.
Boomflies are more dangerous because confusion causes them to cease their very predictable movement patterns and waver around erratically. The range limits also mean there's a good chance you'll get caught in a blast. Red boomflies are slightly less of an issue.
Swarms of spiders are problematic because of their fast movement and tendency to rush you, plus the unreliable knockback.
Crazy Long Legs are very problematic in large numbers due to their rush tactics and the unreliable knockback. If you get the room with four of them, good luck.
Stationary Boils, Guts, and Sacks are much harder to defeat because they tend to be a bit finicky with their hitboxes in the smaller stages (and mother help you if you have to kill them in a room with invincible-shooting-at-you-statues)
Swarmers actually become kind of easy to take out.
Hives and Nests are more irritating because you can't take them out from a distance, Nests in particular because they spawn spiders (whereas the flies spawned by Hives are less of a threat).
Large numbers of Gapers and Frowning Gapers can be a serious threat because of their tendancy to corner you before you can kill enough of them off.
Skinnies become a joke because knockback ruins their already-abysmal speed.
Horfs become easier in many cases because you can kill them through walls where they can't see you.
One Tooth and Tiny Haunt enemies become both easier and harder, since although knockback varies in how it knocks them, the confusion effect can keep them out of your face.
Globins become slightly more threatening but if you can kite them long enough your orbit shots will actually kill them faster.
Gazing Globins are extremely difficult to deal with if there's more than one in a given room, due to their high speed and unpredictable knockback. One just killed me.
Masks and Hearts become problematic. Although you can hit the hearts through walls at short range, the orbital tears limit your ability to take them out at a distance of your choosing. Tbh they were already problematic unless you had flight.
Haven't run into any variations of the Knight enemy yet but I'm guessing they're easier and harder (harder because of your range, easier because the orbit shots can hit their weak points even when they face you).
Tumors become problematic because you have to get close enough to them that dodging is hard, and their spit can be shot at just about any angles. Also they often show up in rooms without a lot of maneuvering room for the player.
Buttlickers are easily dealt with if you have a proper camping spot because you can shoot through walls.
Hosts were already range sensitive so your loss of range doesn't change much.
Walking Hosts, on the other hand, become MUCH more irritating to kill, and the confusion status effect can delay the firing of their projectiles until a random time when they don't even have their necks up. You'll be trying to bait it toward you and suddenly it shoots you dead without warning. I've died five times to these jerks so far. Mother help you if you walk into that quad room setup with the Constant Stone Shooters and Walking Hosts.
You have to get closer to Monstro to hit him but you can confuse him so his difficulty is roughly the same unless you got slapped with some speed downs, in which case you're probably toast anyway.
Haven't faced Gemini in this challenge yet.
Haven't faced Steve ever yet.
Gurdy Jr. is actually harder than Gurdy in my experience. The confusion tears help substantially with the whole "charging you" thing, though.
Pin becomes much easier because you just have to be in his general vicinity, and he gives you lots of time to build up a lot of orbit shots.
Widow becomes harder to defeat because of the difficulty of dealing with spiders and sacks, although a constant orbit-shield makes up for it slightly.
I've only faced Blighted Ovum once during this challenge and I had never faced it before so I can't say much regarding that.
The Haunt becomes a joke. The most dangerous thing about him are his ghost goons who can be knocked into the player if the player isn't careful. After he reveals his other face, just stay to a diagonal of him in your orbit range and he's good as dead. Haven't faced Jingle in this challenge yet.
Larry Jr. becomes relatively easy since you can hit him where he can't hit you.
The Duke of Flies becomes a walkover foe since most of his spawned flies are easily obliterated by your orbital tears.
It's hard for me to gauge whether Famine got easier or harder. I don't run into him often.
Haven't faced the Gurglings in this challenge yet.
Fistula becomes harder because of the unpredictability of your orbits, which can result in parts dying that you werent ready for. Also because it spawns lots of spiders.
Haven't faced Chubs in this challenge yet.
Gurdy becomes mostly a joke. Take out the red pods, then just keep to a diagonal and it can't touch you.
Mega Fatty's difficulty doesn't really change that much.
I've never faced Mega Maw or CHAD at all, in or out of this challenge.
I haven't unlocked the Catacombs yet so I haven't faced any of those bosses.
I haven't faced Dark One or Pestilence in this challenge.
The only Chapter 3 boss that I've faced was Adversary. As it turns out, he's actually hilariously easy to beat in this challenge. His homing brimstone lasers can't hit you if you keep at a true diagonal to him, but your orbit can still wreak his havoc.
That's all I've got so far.
EDIT: The Boomerang is a highly recommended throwing item if it shows up in the shops because it can kill Walking Hosts even when they're not exposed.
173.22.100.59 21:48, 8 January 2015 (UTC)