I clear all 8 scenarios in order, triggering the end credits.
In most cases, I switch to the closeup view of the red nest and rely the game's auto path-finding to lead the yellow ant to the red queen. In a couple areas, the ant easily gets lost, so I guide her manually for a bit. In the last scenario, I intentionally delay the her movements for a few frames to give time for a spider to turn around; without the delay, she gets eaten en route to the red nest.
During the fights, I rapidly press A and B (alternating 2 frames A / 1 frame B), to boost the chances of winning. A random value is selected at the start of the fight, and then compared to a second random value at the end of the fight to determine the winner. The first value must be greater than the second for the yellow ant to win. Every one of the A/B button presses increments the first value, and the fights usually last long enough to increment it well past the second value. When the second value is too large for this to work, I buy more time for button presses by briefly pausing the game mid-fight.
(The YouTube recording is a slightly earlier revision where I didn't press A at the end to close the final dialog boxes. Otherwise, it's identical.)