"add 2p Co-Op" :: Metro: Last Light Redux General Discussions
Zombrex’s mod doesn’t rewrite the netcode entirely. Instead, it uses a Halo: Reach style "firefight" approach combined with screen-sharing exploits. Actually, let’s clarify: True peer-to-peer is still not there. However, Zombrex utilized a Parsec/Steam Remote Play Together wrapper modified specifically for the 4A Engine.
Outlook
Metro 2033 uses a checkpoint-based save system. Co-op requires a persistent game state. Modders would have to invent a new save/load system from scratch.
You might ask: "Modders added co-op to Skyrim and Fallout, so why not Metro?"