




Metal Sonic's green eyes in Memories and Beyond is a huge insight into his character and an insane deep cut
Metal Sonic has had a shocking amount of different eye colors throughout the series. In CD his eyes actually were grey before becoming red post-CD, likely due to technical limitations? They were primarily changed to red to make him more intimidating. The IDW and Mania Adventures shows the eyes flickering to show him "thinking" / "processing". And when he's Super, his eyes glow yellow, which is... more of just a visual showcase than an emotion from what we can gather.
Other eye changes is in Sonic 3, which has the "pupils" shaprening like an animal. Predators do this when preparing to ambush targets by increasing depth of field. Its also famously tied with anger, aggression, and defensive states in cats, which is apporpiate for the scene.
However, the deep cut is that the green eyes come from Mario & Sonic at the Winter Olympics Games, specifically the DS version in 2009. If Metal Sonic is in 1st place or wins, he posssesses green eyes. This implies that he is GENIUENELY happy at winning.
So if green = happy, then Metal Sonic during Memories & Beyond is HAPPY to duel everyone. And that makes him the most Sonic he's ever been. Sonic faces fear and challenge with a grin on his face no matter the threat or power while Metal has always been shown to be angry, annoyed, or stoic. And its convenient that they just so happen to be Modern Sonic's eye color.
I love how Metal Sonic's been portrayed in the series since the IDW comics, he's never felt more "alive" as a character and not just some mook miniboss.