Technically,
the intro is actually full of pull-offs, since in the game and real electric guitar, the ability to pull off makes the green note automatically play and is what propels players through this intro.
Had the first note been green, and then the second red, rather than the reverse, then the whole intro could be termed hammer-ons due to the notes approaching from left to right. This would also make the intro very slightly easier due to the ability to hammer on the first note then pull off to green.