If I am correct, the earlier original version was optimized for a 640x480 resolution. There, the scaling was fine up to the 1024x768 resolution.
But like the OP said, the menu must expand at least by the factor 2 for a HD resolution. For bigger ones(4K), up to 4-times. I think, an option in the game menu would be fine and don't hurt anybody. :)
For me personally the menu in his current state is still too small for a 1920x1080p resolution.
@All the Devs
Thanks for the game! Played a couple of battles the last days. Great as usual.