Use a four-pass hint ladder
First revisit the current room, then check unused items, then repeat unresolved conversations, and finally inspect another available area. This preserves discovery while still narrowing the problem.
Write item properties, not assumed solutions
Describe an object by what the interface lets you do with it. An unusual toy or piece of trash may matter later, but its appearance alone does not prove the intended use.
Mark first-person encounters separately
Steam says Mellow can block, dodge and punch monsters from a first-person perspective. Keep combat observations separate from point-and-click item logic so the two systems do not create false puzzle rules.
Local tracker