Goal. Clear every floor of every stalk, left to right, and beat the boss at the top of the last stalk.
Climbing
Step on any open floor of the current stalk, in any order. Every floor of a stalk, good or bad, must be cleared before the next stalk opens.
A bug is beaten only when your strength is greater than its number, and a tie loses. Winning adds the bug's number to yours.
Nectar adds, honey multiplies, a thorn subtracts (you are lost if it would take you to zero) and mildew halves you, rounding down.
Order is the puzzle. You have 5 and a bug of 5 waits with a nectar of +3. The bug first ties and loses. Take the nectar to become 8, beat the bug for 13, then the boss of 12 falls.
Tricky floors and help
A grower (12 ↑2) gains its growth after every step you take, so face it early. A shielded bug counts double while another bug is left on its stalk.
A padlocked leaf opens once the floor holding its key is cleared. The boss waits until every other floor of its stalk is cleared.
Three stars for the best final strength anyone can reach, two from 80% of it. Hint shows the next floor of a best line, or says none is left; Undo takes steps back, even after a loss. 60 levels in five tiers.