Just putting this out there, in Neon Flatgrass, there is a chance that a fully blacked out version of the Dr. Kleiner NPC will randomly spawn in. This scared the hell out of me and caught me off guard. Be on the lookout for it if you play gm_neon_flatgrass.
I'm very late on this, but i believe that bizarre flatgrass is a flatgrass reskin inspired by the dimension of "Heaven Ascension DIO" from the JoJo game on the ps3 called "Eyes of Heaven"
The way you said that you remember that day you played for the first time while playing sweet soft music reminds me of when I played Roblox back in my first day in May 12 2019 🤗
I don't know if anyone else had had this problem but when I downloaded neon flatgrass and deleted it,it my game permanently neon if anyone had this problem and knows how to fix it please let me know Edit so this wasn't the mod causing problems it was a different mod idk the name
Likely CS Source is needed. Otherwise, obtain Half-Life 2, HL 2 Episode 1 or HL 2 Episode 2. It depends of which game has the textures needed by Bizarre Flatgrass
fun fact : in the contrust in flatgrass at the bottom left building theres the area with the alyx doll at the top of the bottom left building btw. they might have removed it idk