PRGilland | Portal Gun in Black Mesa @PatrickGilland | Uploaded March 2013 | Updated October 2024, 4 minutes ago.
Or Black Mesa in Portal.

Inspired by: youtube.com/watch?v=elES42sns1Y

Remember that famous video that had someone play Half-Life 2 in Portal? And there was a followup with Half-Life Source? It was inevitable that someone did it with Black Mesa.
Except unlike the HL2 example, this game does not crash on a handful of maps. It cashes on a SHITLOAD of maps. It's really unstable.

This was the assets from the mod version of BMS pasted into Portal's folder