|N version||1.4 and later|
Method 1 (Ease/Speed)
Run up the ramp, and jump into the gap between the two tunnels. Wall jump off of the right wall in to the next tunnel. Quickly jump into the next gap. Continue jumping up, being careful not to spend more time than necessary in the line of fire of the chainguns. When you reach the top, walll jump off the right side of the gap between the two tunnels. Grab the switch while still in the air, and quickly drop down the gap in front of you. Just drop and hold right. Continue falling into the gaps until you reach the exit.
Method 2 (AGD/Highscores)
91-4 is considered to be a very challenging level to highscore since in order to obtain a good score, players need to rely on some luck to clip through bursts of chain gun fire. TWA_MATO_Titan currently holds the 0th with a score of 270.225. For a slightly easier route that still garners a highscore, consider emulating tactics used by jg9000, especially near the top part of the map.