Win a game: “Did you lose 100 times first?”
Lose a game: “99 more of them to go”
Lose a hundred games: “Maybe consider 100 more?”
Win a hundred games: “Time to finally check how ranking works”
Lose a hundred games against lower ranked opponents: “Please locate the review button”
Win a hundred games against higher ranked opponents: “OGS ranks do not work properly anyway”
Lose a hundred games against higher ranked opponents: “Shoot for the stars, hit the air, learn to aim better”
Lose a life and death fight: “No tsumego, no party”
Win a life and death fight: “Sometime you succeed, sometimes they die”
Lose 100 life and death fights: “The only tsumego I like is in real games”
Win 100 life and death fights: “Hard work pays out”
Win a game because of winning the last ko, under Chinese-like rules, while not letting the opponent get more than half the dame. That is, allow your opponent to play the dame as ko threats, and still win the ko.
Kill a group in a bent-four shape.
Kill or save a group using play-under-the-stones.
Fight a superko (a triple-ko under western rules, so it does not annul the game).
Win or lose a game because of the ruleset (that is, the winner would change if we switched from Japanese to Chinese or vice-versa).
Play out a losing ladder, but still win the game (I once won a tournament like that! I wasn’t being Lee Sedol-clever, I just really misread the ladder).
Win a game after some number of moves of mirror play.
One achievement per type of seki: seki with two common liberties; seki with one eye each plus one common liberty; seki where one player has two groups with one eye each, and the opponent has a group with two common liberties; seki with one eye each, plus a double ko (if another ko happens in the game, it either means one player has unlimited ko threats, or it’s a triple-ko, depending on the situation).
Specific to OGS: program a sequence of at least 20 moves in the autoplay, that gets played by the opponent.
I had this happen once, where I programmed in the conditional moves to play out a ladder that crossed the entire board, and my opponent actually played it out, since they had mistakenly thought it was a broken ladder.
I think I’ve never had 5 B2-bombers in the same game… But I’ve also never not had three empty triangles in the same game, except maybe games where one player resigned very early.
I didn’t take it seriously either. However, if it were implemented, it would be easy enough to self-report, and a mod could verify the achievement by inspecting the game. A list of approved categories could be published.
A little off-topic, but:
Interesting to look at the loss for each white play in the ladder: roughly 10, 8, 6, 6, 6, … 6, 3·5, 5·9, 1·6, 7·7, 1·1, resignation. I thought I had heard a higher estimate than 6 (¿about 10 or 15?), but I see nothing about it at Ladder at Sensei's Library.