How (and why) we ported Shenzhen Solitaire to MS-DOS

The choice of 320x240 resolution with 256 colors on the VGA adapter is a pretty strange one. I would think that 640x480 with 16 colors would be a much better choice.

- For a card game, you don't need much colors (white, black, red, background), but resolution is critical, as there are many fine details.

- 16 color mode has a special mode where one byte access can write a color to up to 8 pixels. If you get this trick right, then filling large areas with solid color or simple patterns (such as mostly-white card faces) will be even faster than in 256-color mode.

- Subjectively, high-resolution mode with almost square pixels is what makes VGA special compared to EGA. How are you going to brag about you new shiny VGA card if you cannot even show it off? :)

Zachtronics is awesome. Not only do they make some of the best puzzle games in the world, their write-ups are always full of juicy details.

I really liked their modern take on "retro" programming. I am not of the mind that we need to start teaching every developer how to hack away at assembly, but there's no denying that working on limited hardware (like what is still found in embedded devices) benefits greatly from at least a passing familiarity of it. I think that's kind of what their goal was and is with games like TIS-100 and SHENZHEN I/O. Not necessarily to give seasoned assembly hackers fun games to play, though it certainly does, but to give younger programmers an idea of what working with low-level code can look like.

This article has made me want to re-install TIS-100 and see if I can;t finish some of the levels I struggled with. . .

I love Zachtronics games! One of the few complaints I have about them is, they stopped maintaining (actually retired from the AppStore) SpaceChren for iOS. I was happy enough playing the PC version but man it was a bummer. Shenzhen has been also one of my all time favs from them.

My only request for them is please learn the lesson and don't hack a C# game into iOS again! I understand the pain but supporting multiplatform games is hard: do it the right way or just don't ...

Weird that they chose to make it harder for themselves and do it in 16-bit code.