Games like Sky Mercenaries
Games like Sky Mercenaries include Nova Drift, LUFTRAUSERS, BALL x PIT, ZeroRanger, and Vampire Survivors. We matched them by the tags players give Sky Mercenaries on Steam (Indie, Action, Shoot 'Em Up, Bullet Hell, and Arcade): closest matches first, and among equally close ones the better-known games.

Nova Drift
Shared: Shoot 'Em Up · Bullet Hell · Arcade

LUFTRAUSERS
Shared: Indie · Action · Bullet Hell

BALL x PIT
Shared: Action · Bullet Hell · Arcade

ZeroRanger
Shared: Indie · Shoot 'Em Up · Bullet Hell

Vampire Survivors
Shared: Bullet Hell · Indie · Action

Revolution Ace
Shared: Action · Indie · Shoot 'Em Up

Sky Force Reloaded
Shared: Shoot 'Em Up · Bullet Hell · Arcade

Star Saviors
Shared: Shoot 'Em Up · Action · Indie

Bit Blaster XL
Shared: Shoot 'Em Up · Bullet Hell · Arcade

Ikaruga
Shared: Shoot 'Em Up · Bullet Hell · Action

Streets of Rage 4
Shared: Action · Indie · Arcade

Halls of Torment
Shared: Bullet Hell · Action · Action RPG

Savant - Ascent
Shared: Indie · Action · Shoot 'Em Up

Twilight Survivors
Shared: Indie · Shoot 'Em Up · Bullet Hell

BLUE REVOLVER
Shared: Indie · Shoot 'Em Up · Action

Megabonk
Shared: Indie · Bullet Hell · Action

Touhou Fuujinroku ~ Mountain of Faith.
Shared: Indie · Action · Bullet Hell

Nex Machina
Shared: Action · Bullet Hell · Indie

Planes, Bullets and Vodka
Shared: Action · Shoot 'Em Up · Bullet Hell

Cyberhunt
Shared: Indie · Action · Shoot 'Em Up

Exit the Gungeon
Shared: Indie · Action · Arcade

Windowkill
Shared: Indie · Action · Bullet Hell

Touhou Kinjoukyou ~ Fossilized Wonders.
Shared: Shoot 'Em Up · Bullet Hell · Action

UBERMOSH:WRAITH
Shared: Indie · Action · Arcade