Specific Conditions for Achievement 327 (beat Lamb w/o pickups)?

[mondsemmel]

I attempted this challenge once a few years ago, and thought I didn't take any pickups, but still didn't get the achievement. Now I want to give this another go, but with more information.

• I happen to have found an R Key in my last run. Can I trivialize the achievement with this? That is, my character already has some bombs etc., but is it enough if I don't pick any up after using R Key, or would that void the achievement?
  
• Is it okay to pickup items like Skeleton Key (99 keys), or does this void the achievement?
  
• What other things do I need to be aware of?

I'm not remotely worried about the difficulty of the challenge, but I definitely don't want to make another attempt at it, only to discover that I violated some unstated condition somewhere.

[Nazemec]

Items that directly give you thing (like bomb-related items giving you 5 bombs) are okay. Anything taken from the ground is not, even if it was just spawned by an item.
I wouldn't trust your R key idea, but to be honest I'm not sure and can't check the wiki right now (assuming it is mentioned there).

You could use the special seed G0NE S00N if you think it can help. It makes pickups and items vanish after a few seconds, so you won't get a "pickup in front of the door can't avoid taking it" situation. (And it doesn't prevent unlocks either, otherwise I wouldn't even mention it.)


Ah, and to be sure:
List of things that prevent all kind of progress:
- Seeds (except a few special ones)
- Challenges (except for their reward obviously).
- Daily Runs.
- Reruns and Victory Laps (except for a few specific unlocks).
- Any active mod from the mod menu before Mom is killed once on that save (no matter what they do, other saves are irrelevant).
- Enabling the console before Mom is killed once on that save (even if you don't use it).
- Paranoid antivirus programs (or missing rights) preventing the game from creating/editing its save file.

[TamanduaGirl]

Don't pick up any bums. Bums picking up things like hearts or coins count as you picking them up since it is picked up and given something to you in return.