Not out of the box — but the Jaket mod makes it co-op and PvP. ULTRAKILL is a hero & arena shooter game released in 2020, 98% positive on Steam (169,751 reviews), with 3,122 playing right now. $29.99 on Steam.
Co-op through the campaign or PvP in Steam lobbies, with emotes and chat. Hundreds of thousands of downloads and frequent updates. Steam lists ULTRAKILL as single-player, so it won't show up in Steam's own "games we both own" view as something you can play together — Ready Up counts it anyway, marked "Via mod", and you can hide mod-only games with one filter if that's not your thing.
ULTRAKILL is a fast-paced ultra-violent retro FPS that combines the skill-based style scoring of character action games with the unadulterated carnage inspired…
Steam tags: Boomer Shooter, Fast-Paced, FPS, Blood, Character Action Game, Arena Shooter, Spectacle fighter, Retro
Ready Up compares two Steam libraries and shows every multiplayer game you both have — including whether ULTRAKILL is one of them — then helps you pick tonight's game with a weighted roll or a bracket.
Or open the Steam store page.
Tired of ULTRAKILL? The Swap tab finds the closest unowned games of the same type that are newer or rated higher.
Ready Up is a free tool: enter two Steam usernames and it lists the multiplayer games you both own, runs a bracket to pick one, and suggests new co-op games that fit how you both play. Ratings, tags and player counts from Steam and SteamSpy; page updated 2026-09-09. Powered by Steam — not affiliated with or endorsed by Valve Corporation or Microsoft. How the data works · Legal & privacy · All types · Game Pass