It depends on what you mean by 'decent'… Would it be playable and fun? I believe so. Visually it would be limited. Even the Genesis struggled with getting all the enemies and animations and you might notice some slow downs in busy stretches. The SMS version would for sure reduce the number of enemies and will be sparser. But I believe it is possible. My phiosophy on this was a) making a game I loved available on the console I loved 2) Making something I felt 'could have happened back then’
The game was ported to the amstrad, amiga, atari st and others sometime around 1989 I think. When I said a decent port I think I had those comparisons in mind for the master system which never got it's own port. I was mostly just curious to hear what you thought given the incredible job you did with this megadrive port. I definitely value your insight. Excelsior my friend!
Those ports were horrendous but a lot of it had to do with the time, tooling and level of sophistication of the devs at the time. I’m confident all of those could have been much better with modern development comfort and no pressure to develop a product in a few weeks/ months as a small (sometimes 1 person!) team
would be great most of those 8-bit horizontal "256x224" arcade games, like Rygar, Iron Horse, Jailbreak, Ghosts'n'Goblins, Green Beret, Son Son, Rally-X, Kung Fu Master (this one might fit somehow), etc. - but extending such huge effort to these games might be a task for more people using similar development methodology - anyway, it's actually great seeing Black Tiger working that cool! :) (i actually dreamed on being able to do such port years ago, and thanks @rester159 so much for doing it, and showing us how possible it is!)