It says it was released in 2015 but can.t run at 1080p /. I find this strange thus the question. Is it a remake?
This is an Adventure Game Studio game. While the game itself was released in 2015, the engine it uses is much older. From the AGS README:
Originally created by Chris Jones back in 1999, AGS was opensourced in 2011 and since continued to be developed by contributors.
Still, it should expand to fit your resolution. If not, try a different version of the ags executable and/or deleting acsetup.cfg. I use the one installed on my system (Linux-188.8.131.52) for all ags games, and also always delete/rename acsetup.cfg if present.