Program: Enigma Puzzle Game
License: Open Source/GPL
Description: Enigma is a puzzle game inspired by Oxyd on the Atari ST and Rock'n'Roll on the Amiga.
Website: http://www.nongnu.org/enigma/index.html
Other: They have versions for Windows and Mac OS X for installation, and a Zip file there is pratically a portable version - no installation needed when downloaded a Zip file. The game also have translation for a lot of languages.
It's a nice and amazing brain game!
This one is very easy to make portable, because the Zip version of download is pratically the Portable version.
There is no effort to make it portable.
I recall there was an older development test here somewhere.
Just found it: https://portableapps.com/node/27087
It is outdated, but maybe mjashby will pick it up again.