See the article here: Fixing Commandos for solutions to make the game playable. Due to it's age most modern PCs will run the game impossibly quickly making it difficult to play but both Steam and GoG.com version have been patched. There are some important issues with Commandos: Behind Enemy Lines.
COMMANDOS BEHIND ENEMY LINES MISSION 3 FULL VERSION
The missions names are different between American and European copies of the game. Strategy is a key element because you are vastly outnumbered in most missions. You will deal with missions in the North African Desert, Italy, France, and even in Norway. It is your job to lead a team of six men throughout 20 missions across the entire WWII theater. There are 20 missions in total in Commandos: Behind Enemy Lines. Commandos: Behind Enemy Lines is essentially a puzzle game at heart.