World 2 has no mechanic. It plays like normal and time flows normally. Tim can reverse time when he makes mistakes or miscalculations, but he can do nothing beyond that. Most of the levels are achievable without this power, but some levels, most notably, are practically impossible without rewinding time.
Tim is off on a search to rescue the Princess. She has been snatched by a horrible and evil monster.
This happened because Tim made a mistake.
Not just one. He made many mistakes during the time they spent together, all those years ago. Memories of their relationship have become muddled, replaced wholesale, but one remains clear: the Princess turning sharply away, her braid lashing at him with contempt.
He knows she tried to be forgiving, but who can just shrug away a guilty lie, a stab in the back? Such a mistake will change a relationship irreversibly, even if we have learned from the mistake and would never repeat it. The Princess's eyes grew narrower. She became more distant.
Our world, with its rules of causality, has trained us to be miserly with forgiveness. By forgiving too readily, we can be badly hurt. But if we've learned from a mistake and become better for it, shouldn't we be rewarded for the learning, rather than punished for the mistake?
What if our world worked differently? Suppose we could tell her: “I didn't mean what I just said,” and she would say: “It's okay, I understand,” and she would not turn away, and life would really proceed as though we had never said that thing? We could remove the damage but still be wiser for the experience.
Tim and the Princess lounge in the castle garden, laughing together, giving names to the colorful birds. Their mistakes are hidden from each other, tucked away between the folds of time, safe.