Games like New Frontier9
Games like New Frontier9 include Broforce, Dome Keeper, The Escapists, Your Only Move Is HUSTLE, and STAR WARS™ Battlefront™ II. We matched them by the tags players give New Frontier9 on Steam (Strategy, Action, 2D, Shooter, and Choices Matter): closest matches first, and among equally close ones the better-known games.

Broforce
Shared: Action · 2D · Pixel Graphics

Dome Keeper
Shared: Action · Singleplayer · Sci-fi

The Escapists
Shared: Strategy · Pixel Graphics · 2D

Your Only Move Is HUSTLE
Shared: Action · Strategy · 2D

STAR WARS™ Battlefront™ II
Shared: Shooter · Action · Singleplayer

ShellShock Live
Shared: Strategy · 2D · Action

Titanfall® 2
Shared: Shooter · Action · Singleplayer

Half-Life
Shared: Action · Shooter · Sci-fi

Half-Life 2
Shared: Action · Sci-fi · Shooter

Police Stories
Shared: Strategy · Action · Shooter

Mass Effect™ Legendary Edition
Shared: Choices Matter · Sci-fi · Action

Skul: The Hero Slayer
Shared: Action · 2D · Pixel Graphics

BioShock Infinite
Shared: Action · Shooter · Singleplayer

Huntdown
Shared: Action · Shooter · Pixel Graphics

Pixel Gun 3D: PC Edition
Shared: Shooter · Action · Pixel Graphics

SANABI
Shared: Action · Pixel Graphics · 2D

DEADBOLT
Shared: 2D · Action · Pixel Graphics

Kingdom Rush Vengeance - Tower Defense
Shared: Strategy · 2D · Singleplayer

STAR WARS™ Battlefront II (Classic, 2005)
Shared: Action · Shooter · Sci-fi

Half-Life: Opposing Force
Shared: Action · Shooter · Sci-fi

Black Mesa
Shared: Action · Shooter · Sci-fi

Kingdom Rush Frontiers - Tower Defense
Shared: Strategy · 2D · Choices Matter

Terminator 2D: NO FATE
Shared: Action · Pixel Graphics · Shooter

Half-Life: Blue Shift
Shared: Action · Shooter · Sci-fi