Can I screenshot a window that's behind other windows?

Yes. Choose a window and it is captured on its own, even when other windows cover it. It just can't be minimized.

Where are the screenshots saved?

In Pictures\Screenshots, named with the date and time, unless you choose another file or folder. You can also send them to the clipboard instead.

Not of games protected by anti-cheat. KeyRoutines refuses to read the screen while one could appear in the picture.

Choose what to capture: a window, which is captured even when other windows cover it, a region you pick on screen, a monitor, or every monitor.
Save it to a file, by default in Pictures\Screenshots with the date and time in the name, copy it to the clipboard, or keep it as a temporary file that is deleted when the routine ends.
Give a file name ending in .png, .jpg, .bmp or .gif to choose the format; JPEG quality can be set from 1 to 100.
Minimized windows can't be captured, because Windows doesn't draw them.
Screenshots are refused while they could show a game protected by anti-cheat, so KeyRoutines never reads a protected game's screen.

A Hotkey captures the window in front and copies it to the clipboard, ready to paste into chat.

Every … 1 hour, capture a monitoring app's window to a dated file in a folder.

Capture a region for later steps, then Move or copy file puts it into a shared folder.

Setting	What it does
Of	What to capture: a window, a region of the screen, a monitor, or every monitor.
Window	The window to capture, even when other windows cover it. Empty: the window in front.
Refadvanced	A window from an earlier step, for example {{ steps.open_app.window }}.
Region	The part of the screen to capture. Pick it on screen.
Monitor	The monitor to capture. Empty: the main monitor.
Save to	Where the picture goes: a file, the clipboard, or only later steps of this routine (deleted when it ends).
File	The file to save. Empty: your Pictures\\Screenshots folder, named with the date and time. A folder ending in \\ gets that name inside it.
Formatadvanced	The picture's format. A file name ending in .png, .jpg, .bmp or .gif decides it instead.
Qualityadvanced	JPEG quality from 1 (smallest file) to 100 (best picture).

Can I screenshot a window that's behind other windows?: Yes. Choose a window and it is captured on its own, even when other windows cover it. It just can't be minimized.
Where are the screenshots saved?: In Pictures\Screenshots, named with the date and time, unless you choose another file or folder. You can also send them to the clipboard instead.
Can it take screenshots of games?: Not of games protected by anti-cheat. KeyRoutines refuses to read the screen while one could appear in the picture.