Will it make you feel bad about flinging/toppling/portalling all those turrets to their deaths? Probably not, 'cause that shit's fun. Still, it will make you feel sorry for them. Probably.
Harry101UK's new song was, as he writes in the corresponding Steam Community post, originally meant to be featured in a grim Portal web series called The Underground, which ultimately got canceled. He eventually got around to completing the song, however -- it's about a location from the series called The Pit, where "bots are tortured, destroyed, reappropriated, or just left to rot." Yeah.
Here's the music video. If you like Portal's robotic supporting cast, it might make you uncomfortable.