More Toontown Online Changes and Differences 

interesting, do you remember what music played for each battle/cutscene ?

I was almost 8 years old when Sellbot HQ came out. I do remember the darker skies, and tougher factory. I remember maxing at level 12, but sometime in 2004, they changed it to level 50, was a sad day. I can't remember if the music was any different, but I did feel nostalgic for The Big Boss. The only change I know for sure is in December of 2003 at least, the VP spin sound effect was the same as the Cog death spin sound. When I worked for Project Altis, I tried to implement a recreation of Old Sellbot HQ, even with the unused Big Jump stomp, and the spinning sfx for Boss cogs. It's why modern Corporate Clash still has the unused big jump stomp sfx, and the cog death sound when boss cogs do the spin attack. I do remember the slower walk speed and slower factory doors too. The factory had buggier collisions. People would go in the look out, clip through the wall, and skip to the warehouse battle directly. Or could even jump onto an upper portion of the warehouse, and could then reach the silo battles. One bug that existed as well had to do with Factory elevators. It would take you up in the air forever, you would go on the elevator, if the bug occured, you would continue floating into the sky higher and higher every time the elevator moved.

If level 12 was originally the maximum, do you think they planned on having higher level cogs than 12 at some point?

it is possible that theme was used. there's multiple release notes from around the time SBHQ release on test that mention adding new music and sfx. This would of been december 2003

Ah I see. Then I guess it was during that time, I was very young back then so I don't have a recollection of the date, but the Factory theme was DEFINITELY different. Perhaps maybe if the December 2003 files were found we could finally get a midi for the Installer theme.