Underpowered? and a MegaDrive isn't???
Not trying to hurt your feelings, as I'm an Amiga fan as well. But for sure OCS/ECS Amiga is underpowered compared to Mega Drive when it comes to action gaming. Mega Drive just does everything better, from having a slightly faster 68000 CPU, more onscreen colours, better sprites, etc.
AGA Amiga closes the gap with more onscreen colours, and a 68020 CPU as baseline. But other things like sprites are still lacking in their finesse.
Ignoring commercial viability for a moment, the Sharp X68000 would be more suited to the task than an Amiga.