Gitpod is awesome and a really bright team behind it.
However, Repl.it is different in that we're focused on speed and minimal configuration. You don't even need to login to clone a repo and start it.
The URL structure is repl.it/github/<GitHub path>
Try this 2048 implementation in C: https://repl.it/github/mevdschee/2048.c
(You can even run it on your phone!)