Nice game! Maybe make it so you can't swap more than you have (since atm balances just go into negatives) but other than that it's fun!
Thanks for playing! I noticed that bug after uploading but then considered it a feature! I personally consider it like options trading or leverage. Still, there is not negative consequences for debt so that needs fixing regardless.
I'm considering converting this to a webapp, and will add these as the first new feature!