"ECS" compatibility in games is usually all about having 2 MB chip RAM. Show me a game requiring non-PAL/-NTSC screen modes and/or SuperHires and you've got a point.
I've never seen a non AGA game that requires 2mb chip ram or obese Agnus specifically. The only distinction I ever saw was either 1mb chip required specifically, otherwise 512kb chip/512kb fast was OK as well. 'ECS games' were pretty much only 1mb chip ram requiring games, so essentially only an A1000 wouldn't run some non AGA games, other than that any fatter Agnus equipped 1mb chip ram A500/2000 could run all games, obese Agnus was never a requirement.
Ditto with super Denise being completely useless as far as gaming goes. There was no specific screen mode from ECS required, mind you it's not like they were anything useful like 128 colour mode in lo-res as far as games programmers were concerned so there is no 'ECS games' that will fail to run if you have a regular Denise chip.
Let's face it, most games coders couldn't even get 100% out of the original OCS of the prototype A1000 sans EHB mode.
