Multiplayer shoot em up games for PC/Windows with 2-player support

Airstrife: Assault of the Aviators

Players: 4 local, 0 online

Netherspace 2

Players: 4 local, 0 online

Raiden Legacy

Players: 2 local, 0 online

I Hate Running Backwards

Players: 2 local, 0 online

Jamestown

Players: 4 local, 0 online

Mercenary Kings

Players: 4 local, 4 online

Sky Force Reloaded

Players: 2 local, 0 online

Chicken Invaders: Ultimate Omelette

Players: 0 local, 4 online

Söldner-X: Himmelsstürmer

Players: 2 local, 0 online

Kino One

Players: 2 local, 0 online

Zytron II

Players: 4 local, 0 online

Raiden III

Players: 2 local, 0 online

1993 Space Machine

Players: 4 local, 0 online

Raiden IV: Overkill

Players: 2 local, 0 online

Beekyr Reloaded

Players: 2 local, 0 online

Army Men: Air Attack

Players: 2 local, 0 online

Platypus

Players: 2 local, 0 online

Aces of the Luftwaffe - Squadron

Players: 4 local, 0 online

Shoot Many Robots

Players: 0 local, 4 online

ZeroRanger

Players: 2 local, 0 online

Raiden V: Director's Cut

Players: 2 local, 0 online

Burst Fighter

Players: 2 local, 0 online

Aether Drift

Players: 4 local, 0 online

Black Paradox

Players: 2 local, 0 online

AirStrike 2

Players: 2 local, 0 online