This is part of a video series showing the gradual evolution of the Prison in Half-Life 2. It’s not intended to demonstrate gameplay, as most of these levels, in their original form, weren’t playable. Because of the number of levels to cover and the amount of time it takes to clean them up enough to be viewable, these will be kept as quick glances.
This level is produced from the VMF, prison. The level was likely created by David Sawyer.
The prison level you see here is huge and is one of the larger levels that was leaked in 2003. This level is essentially the prison in its entirety at the time, which includes a very different layout from that seen in the final game and also includes sections seen in previous videos albeit mostly iterated upon.
This level also includes an incredibly early version of the shower section seen in the final version of the prison.
While not covered in this video, the level is also unique in that it includes a scrolling cloud layer within the skybox.
Credits to H.Grunt for cleaning up the level so this video could be produced, without his help this video would probably have taken far longer to finish than it should have.