Instead of unlocking optimization-centric parts while progressing through the game, we’ve changed things so that parts like the I/O expander, memory, and logic gates now unlock automatically at the beginning, allowing you to compete with your friends and colleagues as soon as you reach a new puzzle.

As a compromise for new players, advanced parts are now marked as “not recommended” in a puzzle until it’s first solved.


Despite the fact that this is the best thing ever, the piezo buzzer in SHENZHEN I/O does leave a little to be desired in terms of audio.

To fill that gap, we’re introducing the FM BLASTER (FM/iX) by Mountleaf Sound Concepts, “a versatile FM-based tone generator with 10 professionally designed, stunningly realistic preset patches that cover a wide range of musical directions, including classical, rock, plastic, gasp, and techno.”

If you’re using a printed version of the manual, be sure to check the in-game PDF manual and print out a copy of the FM BLASTER datasheet.


Time was when you could tell a good programmer by how few comments they left in their code. There just wasn’t room for any after they filled their chips to the brim with instructions! Kids these days, with their “legible” designs and their “documentation,” I tell you what.

Well, if it happens you’re one of those types, you’ll be happy to know you can add as many comments as you want for free with the new NOTES part.


Everyone knows that good games have tons of achievements! FIRMWARE UPDATE V1.1 adds… four… achievements to SHENZHEN I/O. Maybe one day we’ll think of more? They're not all for solitaire, I swear.


You asked for it, we put up minimal resistance!


What happens when you copy over the code for histograms from TIS-100 without looking at it? I wouldn’t know, because that’s certainly not what I did. Not at all…

Unrelatedly: The histograms for SHENZHEN I/O have been overhauled to be clearer, especially for low-value metrics like production cost. Now they actually make sense!


Not everything we added in this update was cool enough to warrant a screenshot. Here's a list of everything in this update!


  • Added the FM/iX "FM BLASTER", an FM-based synthesizer with one voice and ten instruments, available in the sandbox.
  • Added a ¥0 "note" part that can be placed anywhere in a design to write additional documentation.


  • Pin names are now shown for all pins when tab (show traces) is held.
  • Added Steam achievements to the game related to solitaire and the secret puzzle.
  • Improved the appearance of histograms, especially low-value production cost histograms.
  • Added keyboard shortcuts for the playback controls: space is bound to simulate and pause, E is bound to step, D is bound to advance, and escape is bound to reset.
  • The current code line indicator now fades slightly when that microcontroller is sleeping.
  • In custom LCD screens, a very light gray color can now be used to connect two segments together without the line gray showing up as an actual segment.


  • Most parts are now unlocked at the start of the game but "soft-locked" to discourage inexperienced players from using them prematurely and getting stuck.
  • Changed the behavior of the dst instruction when one or both operands (acc and the new digit) are negative. The new behavior is symmetric with dgt, setting a digit and the sign of the accumulator separately as specified by the "new digit" operand.
  • Modified the "pocket I Ching oracle" puzzle to provide more room for player designs.
  • Modified the test cases for the "aquaponics maintenence robot", "spoiler blocking headphones", "personal sandwich assembler", and "precision food scale" puzzles.
  • Changed the order of a few mid-game puzzles based on feedback about their difficulty.
  • Added a visualization for input to a certain puzzle that needed it.


  • It is now an error to define the same label twice in a single microcontroller.
  • It is no longer an error to block without sleeping in the sandbox.
  • Music is no longer played while a design in the prototyping area is running. Go make your own!
  • Fixed a bug where histograms wouldn't update when returning to the conceptMAIL or conceptCAD menus.