Disclaimer: this is propitiatory software that I am affiliated with. Unity "HotReload". Not Clojure and nothing compared to having an Arcadia repl, but this is some dotnet method patch stunt I recently helped pulling off: https://www.reddit.com/r/Unity3D/comments/10v66xi/we_just_released_a_free_tool_which_lets_you_skip/. This might be interesting for you if you already have a project using csharp. Also this is something you can sell to your team mates (getting arcadia into something existing is probably hard). Maybe there is even a whole recognition of Bret Victor style interactive game development that can grow from this but that is just me dreaming.
Check this: > Spent a few hours using it today and yeah this rules. Even just adding Debug.Logs while the game is running feels like magic, I canβt wait to see what else I can do. Weβve only got three Unity devs at our company but they seem instantly sold. it is funny how mainstream programmers instantly recognize the power of interactive programming but for some reason the knowledge that this is what lisp is about is not mainstream