I have the same. There was some big legal drama regarding the original developers not getting anything from the original publisher, so I think the new listing is by the actual devs?

https://store.steampowered.com/app/1368820/RollerCoaster_Tycoon_3_Complete_Edition/

Just ran through it again, seems to happen after the umbrella puzzle for me.

I have a screenshot but I can’t post it here.

Pixics seems to have a weekly subscription show up after a few puzzles. There doesn’t seem to be a way to play more without subscribing.