This is my first attempt at exporting SDL and I seem to have blundered. If I had ever tested it on any PC other than my own I'm sure it would have been caught in time... Oh well. I didn't really make much progress since the first version.
I get what you're saying about it seeming like a fishy executable since I didn't use any engine. Dunno what can really be done about that other than using an engine (which I'd rather avoid -- I'm too dumb for object oriented programming and 20 levels of abstraction) or compiling to WebAssembly and letting people play in browser. I'll keep it in mind for next time.