The game needs the expansion pack to work, don't forget to activate it!

In Project64, click "Options" then "Settings" in the "Options" tab, you need to uncheck the "Hide advanced settings" box. Then you need to go back to settings, there will be many more tabs, click "ROM Settings", and set the RDRAM size to 8MB.

Filename	Size	Note
City in the Sky 64	6.30MB	Hack