TIS-100 vs Shenzhen I/O vs Exapunks
Updated 26 Oct 2026
All three are Zachtronics assembly puzzle games scored with histograms, and all three are excellent. They differ in what you program, how much story carries you, and how hard they push. The short answer: start with Exapunks if you're new to the studio, TIS-100 if you want pure constraint, and Shenzhen I/O if you like electronics.
Side by side
| TIS-100 | Shenzhen I/O | Exapunks | |
|---|---|---|---|
| Released | 2015 | 2016 | 2018 |
| You program | A grid of tiny nodes passing values | Microcontrollers you also wire on a board | Agents moving between hosts and files |
| Language | Minimal assembly (ACC and BAK) | Assembly with conditional prefixes | Assembly-like, with file and link commands |
| Extra layer | None: just code | Circuit layout and part costs | Story, hacking and zines |
| Difficulty | Hard from the start | Medium, very hard late | Easiest of the three |
| Scores | Cycles, nodes, instructions | Cost, power, lines | Cycles, size, activity |
| Best for | Minimalists | Hardware tinkerers | A first Zachtronics game |
TIS-100
The purest of the three. You get a reference manual and a broken machine, and little else. Each node holds only a few lines, so most of the game is about splitting work across nodes and keeping data moving. It's the hardest to get into and the most satisfying when it clicks.
Shenzhen I/O
You're an engineer at an electronics factory, building products from microcontrollers, memory and displays. You write code and also lay out the board, so solutions trade off between cheaper parts and shorter programs. The datasheets are part of the fun.
Exapunks
Set in an alternate 1997, you write programs for small agents that copy themselves, travel between machines and read and write files. The instruction set is richer and more readable, the story pulls you forward, and the early puzzles are gentle.
Verdict
New to the genre: Exapunks. Love constraints and don't need a story: TIS-100. Like hardware or want the deepest optimisation: Shenzhen I/O. If you finish all three, see games like TIS-100.