D. of the Crown is quite possibly the most universally compatible game for the Amiga.

[Terse]

The first Amiga game "Mindwalker" is well known because it runs on any Amiga.  It's more compatible than DotC or Shanghai for sure, because it's the only one of the 3 that can run on an accelerated A4000 and an unexpanded A1000.

Before someone says DotC and Shangahi run on an unexpanded Amiga 1000, think carefully.

[Terse]

It might be interesting to compile a list of commercial games that ran on 256K.  Aside from Mindwalker, I can think of Racter and not much else.

Maybe Archon, Hacker, Seven Cities of Gold, Hex, One on One or maybe Tass Times?

I'm not even sure if the early Infocom titles could run on 256K.