Just tried Half-Life with my GOTY copy, both on virtual box and magic dosbox. Same result. It doesn’t recognise a resolution lower than 640×480. The best I could do was to add “-window -w 320 -h 200” to the shortcut properties. But it seems to be prone to crashing, and the fullscreen version won’t stretch out the image to fit the screen.
I found others talking about the resolution as well; where they too remember setting it to 320×200 back in the day, and how they couldn’t now. So I’m not going crazy or anything. Those resolutions are just lost to us, though I’m not sure why.
http://forums.bots-united.com/showthread.php?t=3531
I did find a video, where someone found some sort of experimental port of Half-Life for android:
Thought I’ve not tried it yet.