Thanks, I'm glad you liked it!
Sadly I had to cut the story for time, but that's definitely something I'd add in an update!
"Scratch" is a bit of a misnomer in C++, everyone uses SOME libraries of pre-made code just because there's no real reason to completely reinvent the wheel. My engine primarily uses SFML for cross-platform rendering and keyboard/mouse/gamepad input, as well as a LOT of custom code I wrote to serve as a framework for my games and facilitate making games fast. I wrote the engine before the jam started, but everything that makes Merc an actual game was done during the jam