Awesome! I tested this on 16.04 / X11 / nVidia and it worked fine too. Graphics and audio smooth (as you get from DOS games)
On 17.10/X11/Intel it also worked fine in terms of audio, video and playability, and went full screen.
Interestingly on the same machine under 17.10/Wayland/Intel the video wasn’t full screen, but took up an un-scaled portion in the middle of the screen. Like an old 640x480 DOS game on a 1024x768 LCD panel used to. So black border all the way around. Not sure if there is a DOSBox tweak that could be done there.
I noticed you pushed an AMD64 build to the store, do you plan to push i386/armhf ones too? Perhaps leverage the build.snapcraft.io service to make them for you from a github repo?