Having the statusbar open would have shown the problem with that game (Deuteros). It wants the save disk in drive DF1: if the game is started with multiple disk drives, which is very rare.
Simply disable the “Floppy MultiDrive” option for that game so that there is only one disk drive, and then it works fine. Libretro Disc Control interface currently can only operate on the first disk drive.
You don’t want or need to manually make WHDLoad installs from IPFs since they already exist out there. It is possible, sure, because those are the proper sources for them, but if you need to ask how to do them, don’t. Pre-installed Retroplay LHAs are the way to go.