Hey,

Just found this one day while looking up Hammer tutorials on Youtube. It seems to be a level where you create your own level. Sounds weird I know, but there is so much to explain and I think this video covers all of it perfectly:

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The video shows the basics of the editor and the making of a quick level.

Download Link: http://downloads.alex7kom.ru/portal/maps/po_edit_03.zip
Website: http://portal.alex7kom.ru/36/ (Note: It's in Russian so good luck understanding, unless you know Russian)

Remember to read the TXT file readme_e.txt so you know how to load the editor and how to get editing!
Well, have fun!

Also, I take no credit for any of this btw.