What We Know
GRAIN ROT supports single-player. The official framing still describes a co-op-focused experience, so a solo run should be expected to have a smaller margin for error rather than a separate easy-mode progression path.
Steps or Conditions
Choose solo when you want to learn the loop at your own pace, then plan more conservatively around extraction and recovery. Check the displayed version date because solo and small-group tuning are update-sensitive.
What Does Not Work
Do not interpret supported solo play as evidence that solo is easier than co-op. Do not use a complete build route or enemy strategy here; current verified evidence for those deeper tactics is outside this page’s scope.
Evidence and Limits
The official FAQ supports solo availability and its difficulty expectation. The developer’s Steam communication supports the launch-update balance context; exact difficulty values are not claimed.