Games like The Finest Spark
Games like The Finest Spark include Kerbal Space Program, Megabonk, Deep Rock Galactic: Survivor, Universe Sandbox, and Hardspace: Shipbreaker. We matched them by the tags players give The Finest Spark on Steam (Physics, Action, Space Sim, Action Roguelike, and Bullet Heaven): closest matches first, and among equally close ones the better-known games.

Kerbal Space Program
Shared: Physics · Simulation · Space Sim

Megabonk
Shared: Action Roguelike · Bullet Heaven · Action

Deep Rock Galactic: Survivor
Shared: Action Roguelike · Bullet Heaven · Bullet Hell

Universe Sandbox
Shared: Physics · Space Sim · Simulation

Hardspace: Shipbreaker
Shared: Physics · Simulation · Sci-fi

Brotato
Shared: Action Roguelike · Bullet Heaven · Bullet Hell

Elite Dangerous
Shared: Space Sim · Simulation · Sci-fi

EVERSPACE™
Shared: Action · Action Roguelike · Space Sim

V: Rings of Saturn
Shared: Physics · Sci-fi · Space Sim

Soulstone Survivors
Shared: Action Roguelike · Bullet Heaven · Bullet Hell

Space Engineers
Shared: Physics · Simulation · Space

BeamNG.drive
Shared: Physics · Simulation · Realistic

X Rebirth
Shared: Action · Simulation · Space Sim

Kerbal Space Program 2
Shared: Physics · Space · Simulation

House of the Dying Sun
Shared: Action · Space Sim · Simulation

Totally Accurate Battle Simulator
Shared: Physics · Simulation · Singleplayer

Vampire Survivors
Shared: Action Roguelike · Bullet Hell · Action

Deliver Us The Moon
Shared: Action · Sci-fi · Space

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

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

BONEWORKS
Shared: Physics · Action · Singleplayer

Spaceflight Simulator
Shared: Space Sim · Simulation · Space

Dome Keeper
Shared: Action · Sci-fi · Singleplayer

Starpoint Gemini 2
Shared: Simulation · Space Sim · Action