Games like Kuiper Belt Survivor
Games like Kuiper Belt Survivor include Vampire Survivors, Megabonk, BALL x PIT, Halls of Torment, and Enter the Gungeon. We matched them by the tags players give Kuiper Belt Survivor on Steam (Action, Strategy, Roguelike, Action Roguelike, and Bullet Hell): closest matches first, and among equally close ones the better-known games.

Vampire Survivors
Shared: Action Roguelike · Bullet Hell · Roguelite

Megabonk
Shared: Roguelike · Action Roguelike · Roguelite

BALL x PIT
Shared: Action · Roguelike · Roguelite

Halls of Torment
Shared: Action Roguelike · Bullet Hell · Roguelite

Enter the Gungeon
Shared: Roguelike · Action Roguelike · Bullet Hell

Skul: The Hero Slayer
Shared: Action · Action Roguelike · Roguelike

Death Must Die
Shared: Action Roguelike · Bullet Hell · Roguelite

Nuclear Throne
Shared: Roguelike · Action Roguelike · Action

Atomicrops
Shared: Action · Roguelike · Bullet Hell

Dead Cells
Shared: Roguelike · Action Roguelike · Roguelite

Brotato
Shared: Roguelike · Action Roguelike · Bullet Hell

Dungreed
Shared: Action Roguelike · Roguelike · Action

Hades
Shared: Action Roguelike · Action · Roguelite

The Binding of Isaac: Rebirth
Shared: Roguelike · Action Roguelike · Pixel Graphics

Tower of Babel: Survivors of Chaos
Shared: Action Roguelike · Roguelike · Bullet Hell

FTL: Faster Than Light
Shared: Roguelike · Strategy · Sci-fi

Sephiria
Shared: Action Roguelike · Roguelike · Roguelite

Noobs Want to Live
Shared: Roguelike · Action · Bullet Hell

20 Minutes Till Dawn
Shared: Action Roguelike · Bullet Hell · Roguelite

Nordic Ashes: Survivors of Ragnarok
Shared: Action Roguelike · Bullet Hell · Roguelike

Necrosmith
Shared: Action Roguelike · Strategy · Bullet Hell

Risk of Rain (2013)
Shared: Roguelike · Action Roguelike · Action

The Binding of Isaac
Shared: Roguelike · Action Roguelike · Action

Star of Providence
Shared: Action Roguelike · Bullet Hell · Roguelite