Hi there, your source needs to include the Assets, Packages, and ProjectSettings folders so it can be opened in Unity. Please update your source to be in a format that can be opened as a Unity project.
Viewing post in POLTERGEIST jam comments
The ZIP file https://beard.games/poltergeist/poltergeist-code.zip has been updated to include the full Unity project (160 mb). I've moved the ZIP with just the core/scripts to: https://beard.games/poltergeist/poltergeist-code-scripts-only.zip (6 mb)