UltraCraft

Play a solo Minecraft: Java Edition survival world through ULTRAKILL. Mine, build, craft and save your world with Minecraft's real simulation, while ULTRAKILL supplies movement, guns, the native gun terminal and combat.

Every night brings a blood-red sky and waves of ULTRAKILL enemies. Native enemies also replace mapped Minecraft monsters in caves and at night; passive mobs stay. Guns damage mobs and mine blocks, explosions make craters, and the thrown chainsaw cuts wood. Minecraft weapons can hurt the native enemies.

Requires your installed copy of ULTRAKILL and a Microsoft account that owns Minecraft: Java Edition. The companion uses Minecraft 26.3 in its own isolated instance. ULTRAKILL stays visible; Minecraft runs in the background. First Play may ask you to sign in and downloads Minecraft. Java is included. Closing ULTRAKILL saves and closes the companion.

V switches building and guns; E opens inventory; O opens Minecraft options; T or / opens chat or commands; G uses the nearby gun terminal; H returns to camp. To generate a new random-seed world, close UltraCraft and run Reset UltraCraft World.exe in %LOCALAPPDATA%\UltraCraft; it asks first and saves a backup.

Solo only. This is an evolving fan integration; full Minecraft feature parity has not been demonstrated.

Credits: Qua5eyeNimbl3; bridge adapted from PeakCraft by aeironnsarmiento and SkyCraft by chasmlol (MIT). Prism Launcher contributors (GPLv3), FabricMC (Fabric Loader and API, Apache-2.0), and Eclipse Adoptium/OpenJDK contributors (Temurin, GPLv2 with Classpath Exception). Distributed dependencies retain their notices and source links. Minecraft is by Mojang/Microsoft; ULTRAKILL by Hakita and New Blood Interactive. No game assets or account credentials are included. Integration code is MIT licensed and remixes are allowed.