the physics (not chemistry! ;o) is at http://newbrict.github.io/Fe26/js/game_manager.js (fusionRules, towards the bottom encodes what produces what) and it appears to include decay.
it’s not clear to me how you win, since i think you need to go through 52 iron, to 56 nickel, and then decay to 56 iron. but 52 iron itself can decay to 48 chromium. and the application of decay in the main loop doesn’t seem to be random. can anyone clarify?
edit: oh, no, it is randomized. in the lines just below, where decay is compared for inequality with false (ewww).
Man, I really don’t understand chemistry. I just ended up pressing keys randomly and getting different isotopes.
how to discern physics and chemistry: if you can smell it, it’s chemistry.