Season 5 Episodes 20-21 is a two-part episode titled “100”. When it was originally broadcast, both parts were shown on the same night. I presume this is the cut that is included on the Blu-ray that I have: both parts combined into one long (42:18) continuous episode. But on other home media (including streaming services such as Peacock), and presumably in syndication, each of the two parts is instead recut into an individual episode with a running time of about 21:25 each. It seems that part one was originally a minute or so longer than part two, so part one had some jokes cut out and part two had some added in.

So, I nerded out a bit and played both versions side-by-side, taking note of the differences. Here are my findings:

Part one differences
timestamp original timestamp recut
3:50 Pam, onscreen, shouts “I can’t sit in a booth!” 3:50 still photo of Pam onscreen
4:54 “It would be horrible! The only thing I want attached to my funbags are celebrity DJs” 4:51 “It would be horrible!”
6:05 the flashback of Lutz falling while carrying pudding also includes Liz’s/Jack’s reactions
11:27 “The media won’t let you embarrass yourself? Be like Michael McDonald and take it to the streets” 11:19 “The media won’t let you embarrass yourself?”
12:33 recurring hobo pitches sketch to the writers waiting outside “What about a sketch about how the Empire State Building is controlling us with electricity?” “Come on, get out of here!”
15:23 Sideways Jack shouts “The real Jack Donaghy could handle a little gas leak!” followed by a deep sniff
15:54 News interview with drowning biker that Tracy had saved “He just pulled me out of the water and said ‘Don’t tell anyone I did this.’ I didn’t even get a chance to congratulate him on his Oscar” “‘Modesty’ and ‘heroism’; two words forever synonymous with Tracy Jordan”
19:41 Paul’s coworker cuts into his conversation with Jenna “Break’s over, Paul. Crew meeting in Lady Chanterelle’s office. He’s pissed.”
20:39 “Okay, I did call you, but I was not in my right mind. I mean, how could I have been, to call you after everything you’ve done?” Flashback to a few Dennis moments including a new scene in a restaurant, romantically shaking waitress’s hand “It’s Tonya, right? Wonderful service” waitress leaves “Could you maybe not hit on the waitress right in fro–” “CHEW AND SCREW! Run, dummy!” Dennis runs away from table, Liz follows “Ugh, dammit! Dennis! I checked a coat!” 19:54 “Okay, but I was not in my right mind.”
21:19 “No, you know what I feel? You were a mistake” 20:09 “No, you were a mistake”
20:38 “To be continued, dummies” followed by the credits over top of a series of musical flashbacks
Part two differences
timestamp original timestamp recut
0:00 “Previously, on 30 Rock” followed by recap of part one
0:41 Elevator ding “This is us, Ms. Lemon. Let’s walk together like Laverne and Shirley” Kenneth tries to link arms, Liz fights him off “Oh, I’m sorry. I’ll keep talking about the bird!” followed by opening credits
3:26 while throwing cash at crying strippers “How about a little less self-respect and a little more squatting?”
26:29 “OJ Simpson - who texted me earlier today.” 5:31 “OJ Simpson - who texted me earlier today. What should I write back?”
30:21 “Hey, Greta Johannsen, your animal wrangler” “My god, you’re beautiful” 9:24 “Hey, Greta Johannsen, your animal wrangler. I don’t want to alarm my other wildlife, but all the canaries for the coal mining sketch seem to have slipped off to meet Garuda in the sky” “My god, you’re beautiful”

I see that S6E6-7 “Hey, Baby, What’s Wrong” is also a two-part episode that is combined in some places and split in others, so you may be able to expect another post like this for that episode!