I have not seen DOSBox ever ported to OpenVMS, so I decided to take a shot and try. The results you can see below:

DOSBox 0.72 on OpenVMS 8.4 (Alpha) ported and compiled on the ES40-emu simulator on MacBook Air M2 (arm64)
Took about a week of intensive debugging and testing on a fully emulated OpenVMS 8.4.

SDL-1.2.14 is needed for DOSBox to run. Im not aware of any other ported version of SDL to OpenVMS so this one was used.

The DOS simualtion speeds are really horrible since I am running this inside an ES40-emu simulator in the first place.
Im sure it will be better on a real Alpha Server though.

Binary + Sources + Howto are available here: https://astr0baby.online/AXP/OpenVMS/DOSBOX/

VIdeo demo here : https://youtu.be/LaCuKbojgbg?si=pzPWLRWwYR0UiZJJ