A downloadable game

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Subleq is a programming puzzle game about using one operation to create a series of more complicated instructions. This game is inspired by the programming-puzzle games of Zachtronics, and was built to run inside of their latest game, "Last Call BBS."

Subleq stands for "SUbtract and Branch if Less than or EQual to 0." This mouthful of a description doesn't tell you much, but this one operation combined in the right ways is Turing complete. 

The logic behind how a set of subleq-powered operations is derived is surprisingly simple, and my goal with this game was to give you, as the player, the opportunity to build up a set of subleq instructions for yourself. I hope you enjoy :)

Rated 4.5 out of 5 stars
(2 total ratings)
TagsAutomation, Math, programming, Retro


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Click download now to get access to the following files:

subleq.js 23 kB


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how do you change level

Press the number of the level on your keyboard. I probably should have explained that in the description of the game.


This is pretty nice! You really do get the hang of using Subleq after beating each level. Although since the test cases are random, you can pass all three cases while having bugs, which also makes bugs harder to find. Regardless, I had fun squinting at lowercase letters for 30 minutes.

I was able to match or improve all of your best low-char scores (with solutions that truly work in all cases). Here are my improvements, including the code, where slashes separate lines:

Level 48 Charsbam/cb/a/ac
Level 5
8 Charsda/bcm/ad/j
Level 610 Charsbak/n/dbm/n/z/a
Level 78 Charscb/bam/a/ac

Level 69 charsbal/a/z/dbz/j
Level 821 charseb/abm/dc/j/gak/ae/b/fa/bf/a/ad
Level 68 CHARSbak/a/dbm/a
Level 77 CHARSbaz/cb/ac
Level 817 CHARSec/ae/abn/dc/k/ca/bc/a/ad
(2 edits)


Level 815 CHARSea/fb/gc/a/o/ag/efn/be

there is also 7 line solution

Level 815 CHARSea/fb/gc/an/ag/efm/be