The first secret level is accessed from Level 4 Episode 1. The level is called Launch Facility. While going down the last slim stream in Level 4, watch the wall on the left. Just before the exit switch near the last left bend, is a weak spot in the wall. Blow it open and jump inside. If you are going to fast and pass it and end up on the platform in front of the exit switch, you can run ( I find you move upstream faster if you jump ) back to it. When you complete this level, you are returned to Level 5 ,The Abyss, which is the last level of Episode 1. The DNSCOTTY code number for Launch Facility is 106.
The next two secret levels are in Episode 2. The first one is called Spin Cycle. It is accessed from Level 5, Occupied Territory. After you kill the Battlelords standing next to the turning hologram, move to the platform on the right where the switch to the exit door is. Don't hit the switch. Turn back around toward the walkway you just came across. On the wall high up to the right is a switch. Shoot this switch or if you have fuel, you can jet pack to it. This switch opens a panel on the wall to the left of the walkway (facing out from the hologram). Jump or jet pack to the secret level switch. The DNSCOTTY code number for Spin Cycle is 210. This would be E2 L10.
The second secret level for Episode 2 is accessed from Level 8, Dark Side. It is called Lunatic Fringe. After you walk through the monolith, you are transported to a circular room. As you exit the monolith on the wall up and to the left is a weak spot. Blow it open and jump up there. Follow it around to the switch to Lunatic Fringe. When you complete this level you will go to Level 9, Overlord, the last level of Episode 2. The DNSCOTTY code for Lunatic Fringe is 211. This would be E2 L11.
The first secret level for Episode 3 is accessed from Level 5, Movie Set. It is called Tier Drops. On the "Movie Set" (Stage 17B) where the satellite dish is, there's a USA on the fin of the crashed rocket. Press the letters on the fin and the side of the rocket will open to the switch to Tier Drops. The DNSCOTTY code number for Tier Drops is 310. This would be E3 L10.
The second secret level of Episode 3 is accessed from Level 8, Hotel Hell. It is called Freeway. In an area next to the swimming pool is a small waterfall. Jump into the waterfall. On the other side you'll see a hand print switch on the wall in front of you. Go up to the switch. Turn to the right and shoot the two burning pots. Let the fires die down. Then press the switch. Follow the cave. (This is not the secret exit but it does count as a secret place). Remember the movie and be ready to run. As you exit to the left behind the palm trees is the switch to Freeway. When you complete Freeway you'll go back to Level 9, Stadium, the last level of the game. The DNSCOTTY code number for Freeway is 311. This would be E3 L11.
The secret level in Episode 4 is accessed from Level 5, Pigsty. It is called Area 51. In the courtroom, press the picture behind the judge's bench. The DNSCOTTY code number for Area 51 is 411. This woulb be E4 L11.
Episode 1 has 5 levels + 1 secret level = 6
Episode 2 has 9 levels + 2 secret levels = 11
Episode 3 has 9 levels + 2 secret levels = 11
Episode 4 has 10 levels + 1 secret level = 11
Total levels 39
I hope this helps you. These secret levels can be pretty tricky and you don't always come out ahead in the health and ammo departments. ARR29
