Not sure about Windows, but at least on Linux, you can use gamescope to scale the game. To scale it to fullscreen on a 1440p monitor, I used:
gamescope -w 1280 -h 720 -W 2560 -H 1440 ./A Cold Night.x86_64
That said, the game is either poorly paced or broken... I spent a good ten minutes just hovering my mouse to catch snowflakes with nothing to purchase except better value snowflakes... Not exactly riveting gameplay.