The innkeeper has two unused animations. One of them has him scribbling with a large green feather pen, and the other is him reaching for the key rack on the wall behind him.
In the final game, he's only ever shuffling papers around, but there's a broken, partially-implemented script that looks like it's supposed to make him randomly switch between the three animations every few seconds.
In the Monkey Island 2 demo, the artwork for the inn contains a few differences. Most interestingly, there's a key hanging on the wall. Maybe at some point in development, the puzzle to get into Largo's room would have involved getting the key from behind the desk?
If we enter Largo's room while he's gone, he'll show up after a certain amount of time. The first time this happens, he will appear after 30 seconds, but after that, it will take a whopping three minutes for him to show up.
When he catches us the first time, he tells us to "get the $#*&# out of here!".
After that, if we spend three minutes waiting to get caught by him again, he'll randomly say one of the following five lines:
"HEY!"
"GET OUT!"
"GO AWAY!"
"Stop pestering me!"
"You again?!!"
Once he's in his room, he'll stay there until we enter one of the four other areas in Woodtick, or the Scabb Island map. If we try to enter his room while he's in there, he'll randomly say one of the following five lines and then kick us out:
"What are you doing in here again?!"
"Get out of my room!!"
"Scram, kid!"
"Leave me alone!"
"I thought I told you to get out!"
If we put the bucket of mud on the door, Largo will enter a special state. He will now enter the room either as soon as Guybrush moves to the left half of the screen, or after two minutes have passed.
If we leave and re-enter the room after this cutscene, Largo will go right back to his normal behaviour. This means it's possible for him to show up and kick us out even while he's supposed to be at the laundry talking to Marty. If we then go straight to the laundry, Largo will seemingly have teleported between locations.
When we have the voodoo doll in our inventory, Largo will enter another special state where none of the previous rules apply. He will now stay in his room forever until we use the doll on him. The first time we enter with him in this state, he'll say:
"HEY! What are you doing in here?!? Get out of my room! And stay out!"
If we enter his room again after this, his behaviour becomes surprisingly elaborate. First, he will randomly string together three of the following 13 lines:
"Stop bothering me!"
"You're a pain!"
"Why are you following me around?"
"Every time I turn around you're there."
"I can't believe you're in here again."
"Didn't I kick you out of here before?!"
"It's people like you who make people like me who we are."
"You're invading my privacy."
"A man's room is his castle."
"Why can't you leave me alone?!?"
"I oughta beat you up for coming in here."
"You have some nerve, barging in here."
"How dare you come in here again."
Next, he'll randomly say one of the following three lines:
"Get out of my face!"
"Get out of here!"
"Get away from me!"
Finally, Guybrush will randomly say one of the following four lines:
"Oops."
"Yikes."
"Sorry."
"Bye."
If we put the bucket of mud on top of the door and then pick it back up, Largo will never show up unless we either put it back or leave and re-enter. We now have free rein over his room for as long as we like.
