Here are the threads I could find with fewer than 20 comments—again in chronological order:

Ask HN: Why is the 2048 post so popular? - https://news.ycombinator.com/item?id=7378022 - March 2014 (15 comments)

2048 was too easy : welcome 4096 - https://news.ycombinator.com/item?id=7386557 - March 2014 (9 comments)

Simple trick to beat 2048: left up, left down, repeat - https://news.ycombinator.com/item?id=7388699 - March 2014 (3 comments)

2048 with undo - https://news.ycombinator.com/item?id=7389112 - March 2014 (5 comments)

2048 in Augmented Reality - https://news.ycombinator.com/item?id=7391322 - March 2014 (2 comments)

JS1k demo details: 2048 - https://news.ycombinator.com/item?id=7407055 - March 2014 (14 comments)

Show HN: 2048 with shareable replays - https://news.ycombinator.com/item?id=7408918 - March 2014 (4 comments)

2048 Benchmark - https://news.ycombinator.com/item?id=7408952 - March 2014 (4 comments)

How to win 2048 everytime - https://news.ycombinator.com/item?id=7410582 - March 2014 (6 comments)

Invisible 2048 - https://news.ycombinator.com/item?id=7418310 - March 2014 (4 comments)

Why Do I Find 2048 So Damn Addictive? - https://news.ycombinator.com/item?id=7418806 - March 2014 (2 comments)

Words oh so great: 2048 meets Scrabble - https://news.ycombinator.com/item?id=7419264 - March 2014 (5 comments)

Xkcd comic about 2048 game - https://news.ycombinator.com/item?id=7427895 - March 2014 (3 comments)

Flappy 2048 in HTML5 Canvas - https://news.ycombinator.com/item?id=7428175 - March 2014 (17 comments)

Flappy 2048 AI - https://news.ycombinator.com/item?id=7432754 - March 2014 (2 comments)

HN Plays 2048 (democracy) - https://news.ycombinator.com/item?id=7434051 - March 2014 (14 comments)

Show HN: Gameboy port of 2048 - https://news.ycombinator.com/item?id=7434529 - March 2014 (2 comments)

2048 in bash - https://news.ycombinator.com/item?id=7435174 - March 2014 (18 comments)

Flappy + 2048 side-by-side - https://news.ycombinator.com/item?id=7436813 - March 2014 (4 comments)

All 2048 games - https://news.ycombinator.com/item?id=7438716 - March 2014 (4 comments)

2048 Directory - https://news.ycombinator.com/item?id=7439663 - March 2014 (4 comments)

WebRTC 2-player 2048 on same board with matchmaking - https://news.ycombinator.com/item?id=7445906 - March 2014 (8 comments)

2048.py - https://news.ycombinator.com/item?id=7446524 - March 2014 (2 comments)

2048 with Stats - https://news.ycombinator.com/item?id=7446608 - March 2014 (4 comments)

2048 game – How it started? Interview with the author - https://news.ycombinator.com/item?id=7448745 - March 2014 (3 comments)

1125899906842624 - https://news.ycombinator.com/item?id=7448931 - March 2014 (3 comments)

Popular versions of 2048 with previews - https://news.ycombinator.com/item?id=7449160 - March 2014 (2 comments)

What is the optimal algorithm for the game 2048? - https://news.ycombinator.com/item?id=7450244 - March 2014 (13 comments)

2048 showcase - https://news.ycombinator.com/item?id=7459448 - March 2014 (2 comments)

Myo armband controlling 2048 [video] - https://news.ycombinator.com/item?id=7463808 - March 2014 (4 comments)

Ask HN: Why doesn't 2048 have a '1' tile? - https://news.ycombinator.com/item?id=7464533 - March 2014 (2 comments)

Ask HN: how do you commercialize something like 2048? - https://news.ycombinator.com/item?id=7473770 - March 2014 (4 comments)

2048 Golf - https://news.ycombinator.com/item?id=7474824 - March 2014 (2 comments)

Code a 2048 bot on hackerrank - https://news.ycombinator.com/item?id=7481542 - March 2014 (8 comments)

Show HN: I found a way to 'cheat'/solve 2048 (With live demo) - https://news.ycombinator.com/item?id=7486762 - March 2014 (10 comments)

Free Open Source Software and the 2048 Problem - https://news.ycombinator.com/item?id=7490316 - March 2014 (9 comments)

Udacity Course: Make Your Own 2048 - https://news.ycombinator.com/item?id=7536123 - April 2014 (2 comments)

Building 2048 in AngularJS - https://news.ycombinator.com/item?id=7554348 - April 2014 (14 comments)

2048 for stars - https://news.ycombinator.com/item?id=7603732 - April 2014 (2 comments)

A 2048 spinoff to raise funds for cancer - https://news.ycombinator.com/item?id=7606252 - April 2014 (3 comments)

A physics version of 2048 – stellar nucleosynthesis - https://news.ycombinator.com/item?id=7618293 - April 2014 (2 comments)

2048 on 8-bit Sega Systems - https://news.ycombinator.com/item?id=7620914 - April 2014 (4 comments)

Show HN: 2048 Game of Thrones Edition - https://news.ycombinator.com/item?id=7656436 - April 2014 (2 comments)

2048 in Idris - https://news.ycombinator.com/item?id=7668540 - April 2014 (11 comments)

2048 in Emacs - https://news.ycombinator.com/item?id=7705947 - May 2014 (15 comments)

2048 in bash - https://news.ycombinator.com/item?id=7708183 - May 2014 (6 comments)

(Yet another) parody of 2048, where you try to lose as fast as possible - https://news.ycombinator.com/item?id=7713249 - May 2014 (5 comments)

2048, Wolfram Style - https://news.ycombinator.com/item?id=7721685 - May 2014 (6 comments)

2048 gestures - https://news.ycombinator.com/item?id=7780359 - May 2014 (2 comments)

2048 in Erlang - https://news.ycombinator.com/item?id=7869179 - June 2014 (14 comments)

Cubic 2048 - https://news.ycombinator.com/item?id=8022498 - July 2014 (4 comments)

Show HN: Gunoki – Trainyard-and-2048-inspired Puzzle Game for iOS and Android - https://news.ycombinator.com/item?id=8329527 - Sept 2014 (4 comments)

Twilio Plays 2048 – Multiplayer Without Internet - https://news.ycombinator.com/item?id=8498398 - Oct 2014 (3 comments)

Can AI beat 2048? - https://news.ycombinator.com/item?id=8724754 - Dec 2014 (12 comments)

Play 2048, get paid in Bitcoins - https://news.ycombinator.com/item?id=9195167 - March 2015 (3 comments)

Zer0: addictive Web number-game like 2048 between two news from HN ^^ - https://news.ycombinator.com/item?id=11202264 - March 2016 (5 comments)

Show HN: WebRTC Serverless 2-player 2048 Game with Annotated Source - https://news.ycombinator.com/item?id=12788147 - Oct 2016 (13 comments)

Show HN: Hex 2048 - https://news.ycombinator.com/item?id=15890753 - Dec 2017 (3 comments)

Ask HN: What are other awesome games like 2048? - https://news.ycombinator.com/item?id=16471374 - Feb 2018 (3 comments)

Show HN: Adversarial 2048 - https://news.ycombinator.com/item?id=31922891 - June 2022 (2 comments)

x86-64 Operating System to Play 2048 - https://news.ycombinator.com/item?id=36516496 - June 2023 (3 comments)