Astonishing that Scorpion engine is capable of producing code which runs pretty well on my stock A500 and glad to see how it's showcased here.
Guess parallax is, for performance reasons, not an option but the beautifully repixeled art makes more than up for it.
Controls could be a bit more slick, but maybe the original is just like that, i don't know. (my gold standard is Turrican II eversince)