Show HN: TetrisBench – Gemini Flash reaches 66% win rate on Tetris against Opus
50 points
3 hours ago
| 12 comments
| tetrisbench.com
| HN
bubblesorting
2 hours ago
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Very cool! I am a good Tetris player (in the top 10% of players) and wanted to give brick yeeting against an LLM a spin.

Some feedback: - Knowing the scoring system is helpful when going 1v1 high score

- Use a different randomization system, I kept getting starved for pieces like I. True random is fine, throwing a copy of every piece into a bag and then drawing them one by one is better (7 bag), nearly random with some lookbehind to prevent getting a string of ZSZS is solid, too (TGM randomizer)

- Piece rotation feels left-biased, and keeps making me mis-drop, like the T pieces shift to the left if you spin 4 times. Check out https://tetris.wiki/images/thumb/3/3d/SRS-pieces.png/300px-S... or https://tetris.wiki/images/b/b5/Tgm_basic_ars_description.pn... for examples of how other games are doing it.

- Clockwise and counter-clockwise rotation is important for human players, we can only hit so many keys per second

- re-mappable keys are also appreciated

Nice work, I'm going to keep watching.

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vunderba
1 hour ago
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I actually grew up playing the Spectrum HoloByte version of Tetris for PC, which only lets you rotate in one direction. As a result, I ended up playing NES Tetris for years as a kid before realizing it lets you rotate clockwise / counterclockwise!

https://en.wikipedia.org/wiki/Tetris_(Spectrum_HoloByte)

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qsort
1 hour ago
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The worst thing is that the delayed auto shift is slightly off and it messes my finesse. (I used to play competitive tetris as well, but between getting older -> worse reflexes and vision problems I can't really play anymore. Weirdly, finesse muscle memory is still working.)

I don't think the goal is to make a PvP simulator, it would be too easy to cheese or do weird strategies. It's mostly for LLMs to play.

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bubblesorting
1 hour ago
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Hello fellow Tetris nerd with a -sort username :)

On the topic of reflexes decaying (I'm getting there, in my late 30s): Have you played Stackflow? It's a number go up roguelite disguised as an arcade brick stacking game, but the gravity is low enough that it is effectively turn based. More about 'deck' building, less about chaining PCs and C-Spins.

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ykhli
56 minutes ago
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Thanks for all the questions! More details on how this works:

- Each model starts with an initial optimization function for evaluating Tetris moves.

- As the game progresses, the model sees the current board state and updates its algorithm—adapting its strategy based on how the game is evolving.

- The model continuously refines its optimizer. It decides when it needs to re-evaluate and when it should implement the next optimization function

- The model generates updated code, executes it to score all placements, and picks the best move.

- The reason I reframed this problem to a coding problem is Tetris is an optimization game in nature. At first I did try asking LLMs where to place each piece at every turn but models are just terrible at visual reasoning. What LLMs great at though is coding.

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vunderba
1 hour ago
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Interesting but frustratingly vague on details. How exactly are the models playing? Is it using some kind of PGN equivalent in Tetris that represents a on-going game, passing an ASCII representation, encoding as a JSON structure, or just directly sending screenshots of the game to the various LLMs?
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storystarling
1 hour ago
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It has to be turn-based. Even with Flash's speed, the inference latency would kill you in a real-time loop. They're likely pausing the game state after every tick to wait for the API response before resuming.
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ykhli
38 minutes ago
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answered this in a comment above! It's not turn or visual layout based since LLMs are not trained that way. The representation is a JSON structure, but LLMs plug in algorithms and keeps optimizing it as the game state evolves
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OGEnthusiast
2 hours ago
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Gemini 3 Flash is at a very nice point along the price-performance curve. A good workhorse model, while supplementing it with Opus 4.5 / Gemini 3 Pro for more complex tasks.
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burkaman
2 hours ago
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It's actually 80% against Opus, 66% average against the 5 models it's tested with.
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p0w3n3d
33 minutes ago
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Guys, I don't know how to tell you but... Tetris can web solved without LLM...
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segmondy
17 minutes ago
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... and what does this prove? what can you decide to use one LLM to solve over another based on this tetrisbench besides play tetris?
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esafak
1 hour ago
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I imagine this is because Tetris is visual and the Gemini models are strong visually.
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bogtog
1 hour ago
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I figure OP would try and give the models pure text forms of the game?

.....

l....

l....

l.ttt

l..t.

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purplecats
21 minutes ago
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watch link?
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tiahura
1 hour ago
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I'd like to see a nethackbench.
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akomtu
2 hours ago
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It would be more interesting to make it build a chess engine and compare it against Stockfish. The chess engine should be a standalone no-dependencies C/C++ program that fits in NNN lines of code.
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vunderba
49 minutes ago
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My back-of-the-envelope guess would be that 99% of LLMs given the task to build a chess engine would probably just end up implementing a flavor of negamax and calling it a day.

https://en.wikipedia.org/wiki/Negamax

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gpm
1 hour ago
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Comparing against stockfish isn't fair. That's comparing against enormous amounts of compute spent experimenting with strategies, training neutral nets, etc.

It will lose so badly there will be no point in the comparison.

Besides you could compare models (and harnesses) directly against eachother.

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arendtio
2 hours ago
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There are some concepts clashing here.

I mean, if you let the LLM build a testris bot, it would be 1000x better than what the LLMs are doing. So yes, it is fun to win against an AI, but to be fair against such processing power, you should not be able to win. It is only possible because LLMs are not built for such tasks.

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i_cannot_hack
1 hour ago
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Fun fact: Humans were not build for playing Tetris either!
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westurner
41 minutes ago
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Task: play tetris

Task: write and optimize a tetris bot

Task: write and safely online optimize a tetris bot with consideration for cost to converge

openai/baselines (7 years ago) was leading on RL and then AlphaZero and Self-Attention Transformer networks.

LLMs are trained with RL, but aren't general purpose game theoretic RL agents?

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