Another vote for Turrican 1 & 2 here. They were amazing games, I still play them on an emulated A500, but something is lost in the translation to an XBox controller, it needs a Competition Pro 5000 with autofire for best effect.
There’s been a slew of conversions to iOS, but they all fail when you have to use a touch screen in lieu of a decent controller.
My other vote would be for Elite II: Frontier, but my wish was granted earlier this year when Elite: Dangerous went beta. I stumped up £100 for the privilege and despite a few glitches I’m confident that the final release will do the original justice.