Changing the size of memory or changing the ROM version forces a reset of the PET.
The emulator has an IEEE-488 device at address 8. It can be used load and save (.prg) files.
Some programs don't run on ROM1 and some require more memory than the default 8K.
Wolfenstein 3D broke all the molds when it was release in 1992. Escape From PETSCII Castle is a new game inspired by Wolf3D but written for my 1981-vintage Commodore PET computer. Shoot enemies, gather treasures ... and find the elevator to escape.