Dungeon | Classic retro game for the Commodore PET Computer (1979)

In DUNGEON, you wander around a randomly-generated dungeon fighting (or avoiding) monsters and collecting gold. This random dungeon crawler predates the genre-defining game Rogue, so I guess rather than calling it Roguelike, we should call it proto-Roguelike.

You move around the dungeon with the numeric keypad, and you should be able to magically walk through walls (with a small penalty to your hit points) if you press SHIFT with any number. I've seen some reports from players that can't get the walk through walls feature to work when using an emulator. The magic fails because of a bit of control-scheme confusion that arises from the keyboard emulation.

On a full modern keyboard, there are two sets of number keys: one set along the top row, and a second set on the numeric keypad. Early PET keyboards did not have numbers on the top keyboard row—just punctuation marks—so while a modern keyboard treats SHIFT+4 and $ as the same key combination, the PET sees these as two different keystrokes. From the PET's point of view, SHIFT+4 is only SHIFT+4 if it's the correct 4. (Computers are very picky.) When playing on an emulator, I've found that moving around using keypad numbers instead of the top row numbers fixes this problem. If you're using an emulator on a laptop with a small keyboard, you may need to plug in an external keyboard in order to play DUNGEON properly.

There's also a well-known bug in this program: it runs fine in BASIC 2.0 but on a machine with BASIC 4.0, the map will glitch because 4.0 changed the way strings are stored in memory. Robin of 8-Bit Show-and-Tell has uploaded an excellent video where he explains the issue and fixes the bug.