1. find a PC didn't play any RustyLake game (or use VMware)
2. or delete all RustyLake game, all RustyLake relate file, restart PC

one day i play RustyLakeParadise and Samsara Room on PC, i can get achievements on steam. but when i play them another day, achievements don't show even reinstall.
so i play on my mac, achievements show up! but they gone when i play another day. what the???

so i delete all RustyLake game, use shell command "find / -iname '*rusty*' 2>error.log", find and delete all RustyLake relate file, restart mac and reinstall game , achievements show up again!(if you don't know command, you can use other way search and delete)

hope you unlock achievements