There are actually two different roms to choose from: One with a single map that is, in fact, larger than the map Pitfall originally came with (but should be possible to finish in 20 minutes), and another with two different maps: A smaller 125-location “trainer” map with unlimited lives (albeit with a one minute penalty every time Harry dies), 60 minutes to finish the game, and no underground walls; the other map in the second rom is a small yet challenging obstacle course which Harry has to run across in under one minute.
I, on the other hand, have not fully play tested the bigger map, but simulations indicate it should be possible to finish the map in under 20 minutes (just like in the original Pitfall).
To play the bigger map, download the pitfall.xor file as well as the public domain xor.image (source code for Linux and Mac users) tool, and invoke the tool in the same directory as a ROM image of the original Pitfall game:
xor.image pitfall.rom pitfall.xor pitfallX.rom(Note: pitfall.rom, the original Pitfall game ROM, may have the name pitfall.bin. If so: "xor.image pitfall.bin pitfall.xor pitfallX.bin")
This will create a ROM image—pitfallX.rom—that can be played in Stella or any other 2600 emulator. It is probably also possible to download it to a Harmony Cartridge or even burn an EPROM to play it on a real 2600.
The resulting pitfallX.rom has the following cryptographic sums:
md5 5ed1d839f908f580220d6cf487633f90 sha1 fcb9b2068e05017e98c6502e0cb685f1aee3b6db sha2-256 fe6be7879e58cc29e1fbbf6008a69244004c2b6b6c477d92a8b960d65503b7b7 rg32 1dfbdd7cc09ca731aca06f19f767f8bce15a97a1e5f1865933844a5a99e1dc4e