It’s just a Jerboa thing for now, you can browse other instances with out logging into them but Jerboa doesn’t have a way of doing that implemented.

Dungeon Crawl Stone Soup. It’s free and open source available as a download or in browser here. Not sure if your familiar with traditional roguelikes, but it’s basically a permadeath turn based rpg. I finally picked it back up recently and have been addicted. Finally got my first won today after some 300 games.