1
Pick an attachment, then tap a pad. Dashed circles show reach. Keys 1–0 pick, Space opens the door.
2
Every tool has two upgrade paths. Only one can go all the way to tier 3. Tier 3 on the top path is usually an ability.
3
Set-in mess shrugs off anything that isn't its specialty. Hidden mess (dashed) needs a tool that can see it, or an air washer nearby.
4
Every tenth wave, a dry-filter machine shows up. It leaks dust the whole way down the hall and it does not care about wet floors. Bring everything.