Made it past Elvis, couldn't make it past the Prisoner fight. I'm not sure what his deal is. At first I thought he was a zombie, and tried for a "revive kills zombie" strategy, but only succeeded in healing both myself and the prisoner, so I don't know why a player would want to use a potion on themself and the enemy simultaneously.
I'm embarrassed to admit that I did not realize you could click on the code commands on the third "step" of the player's turn until after I read the comments after my first playthrough. I'm not sure what the differences between "loop" and "return" are though, or why someone would want.
Regardless, this is a fun game, and I'd love to play the complete version. If I can ever figure out how to defeat the prisoner.