Regarding future features: I was also thinking about multiple shots, but I just tried it, and it already will do multiple shots! I'm not sure if it matters, but I have an AutoHotkey script with a bunch of hotsrings that is always running in the background, so I assigned Alt+Shift+R to run RaptureReplica.exe. That is how I "call" RR. It appears that Windows will run multiple instances of the exe. Each shot will stay open until I right-click it. So that's cool.
Other ideas:
-Allow increase/decrease of opacity/transparency via mouse wheel up/down, when hovering over the shot.
-Auto save the last X number of shots in some backupfolder. Auto-name them "Raptured-<date and time>" or something like that.

FYI Short screencast:
https://app.screencast.com/fVgY4QvY940HxI didn't record all of both monitors, because that would be too wide to view. This shows half of my primary monitor (on the left; set at 125%) and half of my external monitor (on the right, set at 100%). You can see that RR handles the two scales pretty well!