Enter the room in ball mode and let the hoppers jump against the wall a couple of times. Between hops, unmorph and shoot the lower hopper. Roll under the top hopper until it goes off camera to the left.

Requires:

"Morph"
"canPrepareForNextRoom"
{
  "enemyKill": {
    "enemies": [
      [
        "Blue Sidehopper"
      ]
    ]
  }
}
"canCameraManip"