Games like Monster Killer
Games like Monster Killer include Rhythia, Nodebuster, Bit Blaster XL, Click the Button, and Vampire Survivors. We matched them by the tags players give Monster Killer on Steam (Casual, Point & Click, Arcade, Incremental, and Shooter): closest matches first, and among equally close ones the better-known games.

Rhythia
Shared: Casual · Arcade · Point & Click

Nodebuster
Shared: Casual · Incremental · Arcade

Bit Blaster XL
Shared: Arcade · Shooter · Casual

Click the Button
Shared: Casual · Incremental · Point & Click

Vampire Survivors
Shared: Bullet Hell · Casual · Arcade

Shelldiver
Shared: Casual · Incremental · Arcade

Digseum
Shared: Casual · Incremental · Point & Click

Cookie Clicker
Shared: Casual · Incremental · Indie

To The Core
Shared: Casual · Incremental · Arcade

That's not my Neighbor
Shared: Casual · Point & Click · Arcade

Planes, Bullets and Vodka
Shared: Casual · Arcade · Shooter

Berry Bury Berry
Shared: Incremental · Casual · 3D

Keep on Mining!
Shared: Casual · Incremental · Arcade

Timberman
Shared: Casual · Arcade · Incremental

Click and Conquer
Shared: Casual · Incremental · Arcade

Astro Prospector
Shared: Casual · Incremental · Bullet Hell

Boxes: Lost Fragments
Shared: Point & Click · Casual · 3D

Crab Champions
Shared: Arcade · Casual · Shooter

A Game About Feeding A Black Hole
Shared: Casual · Incremental · Arcade

Outhold
Shared: Incremental · Casual · Arcade

Bills Must Be Paid
Shared: Incremental · Casual · Arcade

Fishing Inc
Shared: Casual · Incremental · Arcade

Poop Clicker
Shared: Casual · Point & Click · Arcade

Gorogoa
Shared: Casual · Point & Click · Indie