12345 (chaotic_iak)


12345, a puzzle game where 2+2=3 and 5+5=0. – [Author’s description]

[Play Online (HTML5)]


  1. Oh, wow, this is very good. Level 15 (“Less Than Helpful”) I just completed but only through haphazard fumbling. Has anyone found the proper linchpin solution for that one?

    • It’s kinda hard to explain, but you just want to isolate one of the blocks on either side to sort of rip the barrier apart. Here’s a GIF.

      Anyway, this is awesome! Lots of mechanics, but the levels all felt very reasonable and not too cluttered. I had to finally break out a pad of paper to figure out what number combination I was going for in the last level.

    • Oh hey I’m here.

      Yeah, sorry for Level 15 and 29, which is kind of simply trying stuff and hoping for luck. But thanks for enjoying my game!

  2. For calculating numbers, it helps to think in powers of 2. The “1” is a 1, the “2” is a 2, the “3” is a 4, the “4” is an 8, and the “5” is a 16. Then, combining blocks adds numbers as normal, and a sum of 32 (i.e. two “5”‘s) annihilates itself. A “+” doubles, and a “-” halves (except it sends 1 to 0). This makes, say, the necessary set of combinations on the last level obvious (look at the starting sum and hence how much you have to remove), as well as the level that’s filled with blocks with a single “+” in the middle (look at the starting sum and hence how much you have to increase it by).

  3. Hmmm… “Sequel”, kind of. More of a spin-off than an official sequel (which increments the version number) though.