Really interesting, thanks for sharing. Would you mind sharing a bit more information on the current setup and costs? e.g. which Vultr compute product is being used, any block storage added, etc.
Something you might consider as the instance grows is Hetzner server auctions. These give you a dedicated server for a very good price and include unlimited bandwidth.
I think pricing and product transparency would encourage users of this instance to contribute to the upkeep :)
Edit: I didn’t see c/Rust:Meta existed before… I see you’re way ahead of me on cost transparency.
ADOM was always my favourite, but Dungeon Crawl: Stone Soup is my go-to these days.
Shattered Pixel Dungeon on android is also fantastic and has wonderful touch screen controls.