Cosmonaut is a mod I made for Half-Life 2: Episode 2 between April of 2018 and May 2019. It contains 9 levels. (7 traditional levels, an intro level and an outro level with credits). Each level has a different environmental theme and different game play scenarios. I started making Cosmonaut for a mapping challenge that took place on RunThinkShootLive.com called NostalgiaVille. After it won first prize, I decided that I would continue to develop it and expand it so I could enhance my environment and level design skills.
Cosmonaut on Mod DB - https://www.moddb.com/mods/cosmonaut