Games like PopSlinger Vol. 2 - Loveless
Games like PopSlinger Vol. 2 - Loveless include UFO ROBOT GRENDIZER – The Feast of the Wolves, Mirage Feathers, ICEY, Beat Hazard, and Furi. We matched them by the tags players give PopSlinger Vol. 2 - Loveless on Steam (Side Scroller, On-Rails Shooter, Bullet Hell, Hack and Slash, and Shoot 'Em Up): closest matches first, and among equally close ones the better-known games.

UFO ROBOT GRENDIZER – The Feast of the Wolves
Shared: Side Scroller · On-Rails Shooter · Bullet Hell

Mirage Feathers
Shared: On-Rails Shooter · Bullet Hell · Shoot 'Em Up

ICEY
Shared: Side Scroller · Hack and Slash · Female Protagonist

Beat Hazard
Shared: Bullet Hell · Rhythm · Shoot 'Em Up

Furi
Shared: Bullet Hell · Hack and Slash · Shoot 'Em Up

Knightmare Tower
Shared: Side Scroller · Bullet Hell · Hack and Slash

DRAINUS
Shared: Shoot 'Em Up · Bullet Hell · Shooter

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

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

Touhou Koumakyou: New Classic - the Embodiment of Scarlet Devil
Shared: Bullet Hell · Shoot 'Em Up · Female Protagonist

Teenage Mutant Ninja Turtles: Shredder's Revenge
Shared: Side Scroller · Beat 'em up · Arcade

Touhou Hero of Ice Fairy
Shared: Bullet Hell · Side Scroller · Female Protagonist

Warhammer 40,000: Shootas, Blood & Teef
Shared: Side Scroller · Bullet Hell · Shoot 'Em Up

The Vagrant
Shared: Side Scroller · Hack and Slash · Female Protagonist

Deathsmiles
Shared: Bullet Hell · Shoot 'Em Up · Side Scroller

Streets of Rage 4
Shared: Beat 'em up · Side Scroller · Arcade

Pistol Whip
Shared: On-Rails Shooter · Rhythm · Shooter

Dead as Disco
Shared: Hack and Slash · Beat 'em up · Rhythm

PATAPON 1+2 REPLAY
Shared: Rhythm · Side Scroller · Beat 'em up

Touhou Tenkuushou ~ Hidden Star in Four Seasons.
Shared: Bullet Hell · Shoot 'Em Up · Female Protagonist

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

Huntdown
Shared: Side Scroller · Shoot 'Em Up · Shooter

LUFTRAUSERS
Shared: Bullet Hell · Shoot 'Em Up · Arcade

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