Trying to preform a viable all endings run and just wondering if the ending counts as both since it technically goes to both endings but just displays -1 or would you have to do them both separate.

Hey! An ending counts if the Ending screen is shown. If you manage to get an ending like Ending 12 and you get the Ending -1 immediately after, both endings count. As long as the Ending Screen is shown it counts towards the all endings run.

As long as its a -1 screen