[dmr_92]

https://www.thinking.withportals.com/ was (is?) the big community for this. I was part of it around the time Valve released their easy map editor (the "perpetual testing initiative")---more than a decade ago now. I had the pleasure of testing the editor before its release. It was an exciting time!

Sadly that editor was geared towards single-player maps, whereas my interest was always in the coop ones. If you'll forgive the shameless plug, https://steamcommunity.com/sharedfiles/filedetails/?id=89692... was my favourite to make. I put a lot of time into that, but sadly I lost the hard drive with the map's source files some years ago. It's done quite well on the workshop---which always surprises me. I had very little idea about level design or what constitutes a fun puzzle. Beginner's luck, maybe?

It was a lot of fun/pain/curiosity to work with and fight Valve's hammer editor. I remember thinking "this feels like a tool designed to make half-life maps". I can still remember tying brushes to func_detail entities so that they wouldn't contribute visleaves. Good times!

While I'm at it: I'd recommend the "sendificator" series: https://steamcommunity.com/workshop/filedetails/?id=29165303... . These introduce a new puzzle element entirely contained within the map file. I'm guessing it must use some kind of lua script to implement it, since it's entirely contained in the map.