Games like Topspace
Games like Topspace include Timberman, Sky Force Reloaded, Planes, Bullets and Vodka, Vampire Survivors, and BALL x PIT. We matched them by the tags players give Topspace on Steam (Top-Down Shooter, Action, Score Attack, Singleplayer, and Casual): closest matches first, and among equally close ones the better-known games.

Timberman
Shared: Casual · Action · Singleplayer

Sky Force Reloaded
Shared: Top-Down Shooter · Action · Arcade

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

Vampire Survivors
Shared: Singleplayer · Casual · Action

BALL x PIT
Shared: Action · Top-Down Shooter · Arcade

Broforce
Shared: Action · Pixel Graphics · 2D

Cyberhunt
Shared: Action · Casual · Arcade

LUFTRAUSERS
Shared: Action · Arcade · Singleplayer

Bit Blaster XL
Shared: Action · Shoot 'Em Up · Arcade

12 is Better Than 6
Shared: Action · Top-Down Shooter · Singleplayer

Halo: Spartan Assault
Shared: Top-Down Shooter · Action · Singleplayer

Hotline Miami
Shared: Action · Pixel Graphics · Singleplayer

Hotline Miami 2: Wrong Number
Shared: Action · Pixel Graphics · Top-Down Shooter

DoDonPachi Resurrection
Shared: Top-Down Shooter · Action · Shoot 'Em Up

Kill The Crows
Shared: Action · Top-Down Shooter · Arcade

Rhythm Doctor
Shared: Singleplayer · Action · Pixel Graphics

Polygoneer
Shared: Action · Casual · Singleplayer

METAL SLUG
Shared: Action · Arcade · 2D

Shower With Your Dad Simulator 2015: Do You Still Shower With Your Dad
Shared: Arcade · Casual · Action

20 Minutes Till Dawn
Shared: Top-Down Shooter · Shoot 'Em Up · Singleplayer

Crimzon Clover World EXplosion
Shared: Action · Top-Down Shooter · Arcade

Gang Beasts
Shared: Action · Local Multiplayer · Casual

Duck Game
Shared: Action · Local Multiplayer · Pixel Graphics