Multiplayer games for PC/Windows with 2-player online support

Magic the Gathering: Duels of the Planeswalkers 2013

Players: 2 local, 2 online

Fallout: New Vegas (NV-MP)

Players: 0 local, 4 online

Journey

Players: 0 local, 2 online

Deadfall Adventures

Players: 0 local, 2 online

Tropico 5

Players: 0 local, 4 online

CastleMiner Z

Players: 0 local, 8 online

Toy Soldiers: Complete

Players: 2 local, 2 online

Homefront: The Revolution

Players: 0 local, 4 online

Defense Grid 2

Players: 2 local, 2 online

Gunscape

Players: 8 local, 8 online

Spintires

Players: 0 local, 4 online

Titanfall

Players: 0 local, 4 online

Haunt Chaser

Players: 0 local, 4 online

Zombie Kill of the Week - Reborn

Players: 0 local, 4 online

ARK: Survival Evolved

Players: 0 local, 4 online

Star Wars Battlefront (2015)

Players: 0 local, 2 online

Act of Aggression

Players: 0 local, 4 online

Quake 2: Co-Op Or Die!

Players: 0 local, 4 online

Tower 57

Players: 2 local, 2 online

Sentinels of the Multiverse

Players: 4 local, 4 online

Object N

Players: 0 local, 4 online

Insurgency: Sandstorm

Players: 0 local, 8 online

8-Bit Armies

Players: 0 local, 7 online

Nature's Zombie Apocalypse

Players: 8 local, 8 online

Looterkings

Players: 0 local, 4 online