One Little Rat now has a shop system! It even has a buy-back feature, in case you sell something by mistake.

There is no functionality for selling ammunition at this time, though, and I plan to have ammunition available in shops only in bulk. This is in the interest of keeping things simpler to code. Too many projects have failed due to over-ambition and I am doing what I can to make this project reasonable to create while still making it a fun mod. Also, the same sort of ammunition system is implemented in Zelda games and it works fine there, so I feel it should work here as well.