I was looking for an "instant replay" program with recording notifications for Linux and found this extremelly easy program mimmicking shadowplay. Might aswell share it here since its pretty hard to find:

[youtube]https://www.youtube.com/watch?v=SOqXusCTXXA[/youtube]

Download link: https://git.dec05eba.com/gpu-screen-recorder-ui/

Its a neat frontend & overlay for a program called "gpu-screen-recorder", the downside is you have to enable Instant Replay everytime you boot