This version of Luigi, aka. Alter Luigi (Classic Era) is from ~
Five Nights at Sonic's: Mega Merge Max Mix.

(This version is also supposed to resemble the style of Sonic Mania.)

A former Night Guard... And now, just being as the Survivor and the only one
of existing from all the Past Protagonists.

He faces off against Alter Dr. Golden and the other Antagonists of all installations from FNaS 1-6: DD in the game, where he is imprisoned in
the Arcade Machine of Mega Merge Max Mix.

In this version, Alter Luigi lost his cap and doesn't have it on his head,
due to the events in FNaS4: DD.
Alter Nightmare Sonic has kept the hat and mocks Alter Luigi for
losing it while escaping from the ruins of the pizzeria on South Island.

P.S. Alter Luigi after escaping the abandoned pizzeria didn't even have a chance to report about the Evil Clones to the authorities. Because soon he was moved by an unknown force to Angel Island, to Alter Dr. Golden's Castle and nobody knows that the Green Brother has disappeared.

Alter Luigi longs to escape the Arcade Machine and experience freedom...
Will his dream come true?

And is Alter Luigi really alone, who faces the adversaries by himself?

Or is there someone, that support the Green Brother and unconsciously... becomes and acts as "The One" with the other half, that is safely staying in another world. And just when Alter Luigi falls, he get another chance and makes another attempt to survive the night.

Or maybe something better, than just freedom, will arrive to him in the soon future?