Oracle VirtualBox (free) + a Windows 98 ISO (you provide).
The HD version uses a modern engine but keeps the exact same gameplay, sprites, and difficulty. It runs natively on Windows 10, supports 1080p/4K, and has working saves. how to play commandos behind enemy lines on windows 10
Regardless of which method you use, press F10 to quick-save every 10 seconds. Commandos is unforgiving. You will die. You will reload. And you will love every second of it. Oracle VirtualBox (free) + a Windows 98 ISO (you provide)