The game HyperRogue is very interesting. Its main gimmick is that it’s played on a hyperbolic plane (surface with negative curvature) instead of an Euclidean plane (surface with zero curvature) like 99.99% of 2-D games are. Playing in this kind of geometry is compellingly mind-bending. Other than the geometry involved, the main way the game differs from typical roguelikes is that the player character doesn’t gain levels or skills in the course of play — instead, the game opens up new “lands” with new environmental challenges and/or monsters with new attributes as the player demonstrates their skill by meeting the unlock requirements for each land.

The game supports “achievements”, where whenever your gameplay meets the condition of some challenge (some very easy, some nightmarishly hard, most of medium difficulty), it records this in a log file. Of course, met achievements aren’t all that the log file contains, but it’s nice enough to start each “met achievement conditions” record with “ACHIEVEMENT” and a marginally-descriptive achievement name, followed by other relevant information. Unfortunately, you can’t get a list of your fulfilled achievements merely by running  grep '^ACHIEVEMENT ' hyperrogue.log  because the game logs when you fulfill an achievement’s conditions separately for every run, not just the first run to fulfill it. So, to extract the records of each achievement’s first fulfillment, we ignore any record with an achievement name we’ve seen before and print out the line otherwise (ie, if we haven’t seen it before), which is nigh-trivial in awk [link]:

/^ACHIEVEMENT / {
    if (!($2 in ach)) {
        ach[$2] = 1;
        print;
    }
}

At 86 characters, it’s the fifth example from me of “twitcode” (programs under 140 bytes). And being in awk, it’s the fifth language I’ve twitcoded as well.