Hey Random,
I looped the track a few times and after giving it a listen I'd say that it has a very open ended feeling. The track is inherently happy sounding however if looped and added with some sinister visuals it would be very easy for it feel forced or fake happy. Like there is something ominous underneath. Which given your flash horror game description may fit perfectly.
I will say since the song does not have anything inherently dark in it like minor or dissonant melodies/chords. So if you're inherently trying to make it sound darker I would add something subtle and dark. Like making the bass more distorted or some background quiet high frequency ambience that occurs halfway through the loop.
Here is something I made a while ago that might help with ideas.
https://soundcloud.com/musicbyajargie/the-darkness-of-love/s-1R0dWebxC36?si=dabf...
Your song music wise has complexities and I like it, I would say check out uploading files to Soundcloud instead of Youtube since it's easier to loop and doesn't compress audio as heavily as Youtube.
