$2000-$3fff &D (2014) | Hacker News Reader

$2000-$3fff &D (2014)

csdb.dk

46 pointsluu10 comments

This was my entry to the Ludum Dare 31 game jam—the theme was “entire game on one screen”. The original page can be found here (maybe I should link to this rather than the cracked version on my site…): https://web.archive.org/web/20150106204654/http://ludumdare....

A friend of mine mid 90s was doing a clean room rewrite of doom (for fun, just to learn) and didn’t have any bounds checking on his maze - so it was possible to wander off into program memory and shoot variables. (Classic Mac OS, no memory protection)

Shooting variables sounds very satisfying!

I really wish that the text for this was transcribed so where so I didn't have to ake a screenshot of a gif at just the right moment to read it.

The visible text in the GIF is:

  $2000-$3fff was made for the Ludum Dare
  #31 Game Jam in December 2014. It is
  actually more than just a game. Some of
  you will say it's crap, but we would
  point out that it's both a game and a
  piece of art. The idea and concept is
  actually great:

  This is the official description of the
  game:

  "$2000-$3fff is a Commodore 64 program
  which displays its entire memory on the
  screen, then draws missiles into it.

  Use a joystick in port 1 to target your
  dangerous explosive weapon. If you
  don't have a C64 handy, feel free to
  use an emulator like VICE.

  Defend program data and program code
                                     01/02

Normal spaced version:

$2000-$3fff was made for the Ludum Dare #31 Game Jam in December 2014. It is actually more than just a game. Some of you will say it's crap, but we would point out that it's both a game and a piece of art. The idea and concept is actually great.

$2000-$3fff is a Commodore 64 program which displays its entire memory on the screen, then draws missiles into it. Use a joystick in port 1 to target your dangerous explosive weapon. If you don't have a C64 handy, feel free to use an emulator like VICE. Defend program data and program code.

Looks cool... anybody want to do an explain-like-im-not-a-c64-esoterica-expert on what this is?

I also don’t know. Reading the comments in the OP, it seems it’s some kind of defence game where successful attacks (ie those you fail to defend against) modify the game code, causing surprising behaviour.

Yup, Missile Command, but the game code is located in bottom of the bitmap ('frame buffer' if you like), so when the line drawing code writes to that area it will modify it. Shenanigans!

The bitmap would end before $3fff though, since it's only 8000 pixels.

Missile Command, except instead of cities at the bottom of the screen, it's the data and code of the game (which is resident in video RAM). Fail to intercept a missile? Game gets corrupted.

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