Cobalt Core

Each run of Cobalt Core puts you in command of a spacecraft navigating a series of combat encounters on a single horizontal axis. You issue orders by playing cards — raising shields, firing cannons, or sliding your ship left and right to dodge incoming missiles and expose enemy weak points. The tension comes from reading your opponent’s position and intentions a half-second before they resolve: a dodge that sidesteps one volley might walk you directly into another. Winning a fight is less about raw damage output than about controlling the lane and dismantling the enemy’s ability to threaten you.

Rocket Rat Games built the crew system so that each character brings a distinct card pool and personal story arc. You take three crew members into a run, mix their decks together, and navigate both the tactical layer and an unfolding narrative about escaping a time loop. Hundreds of card combinations exist across the roster, and each card offers split upgrade paths rather than a single improvement, which means the shape of a deck shifts meaningfully depending on which branch you take. The stated character-and-ship permutations are substantial even before difficulty modifiers enter the picture. Players who prefer deterministic puzzle-solving over improvising with random card draws will likely find the variance frustrating. Daily challenges layer on additional modifiers — single-character runs, self-scrambling ships — and feed into leaderboards for those who want a competitive measure. The soundtrack, over ninety minutes of original music, was composed by Aaron Cherof, known for work on Minecraft.

Cobalt Core released on November 8, 2023, and received several hotfixes within its first weeks. A version 1.1 update arrived in June 2024 adding new enemies, followed by incremental patches through 1.1.2. The 1.2 branch began in August 2024 and continued through a 1.2.5 release in July 2025, which also brought Linux support. Patches have continued into early 2026, reaching 1.2.9 in February of that year. The game descends from Rocket Rat Games’ earlier project Sunshine Heavy Industries, which received an IGF Honorable Mention for Excellence in Design in 2022.