Surprised no one has got this classic working as it does not work out of the box (You have to create ~/.alex4/alex4.ini and set some graphics settings so it displays correctly on the 320x240 screen. You also then have to remap some keys to Ctrl and Alt to properly play the game).
I created a github repo with some instructions, icon, and launch script for convenience. Also in the repo are the beginnings of a key mapping reference guide. I may write up a key mapping tutorial if no one beats me to it (Also surprised I have not seen this either, other than briefly in the Wolfenstein thread).