The hidden bags can be found at the following locations. Each level has three bags, with thirty bags in total.
Prologue: The Edge
Checkpoint B. Immediately after entering the building and climbing up onto the vent, you will find the bag (required for level completion).
Checkpoint B. Drop down, and survive the guard ambush. Run up the red stairs, and go through the first red door. Turn left, and run to the end. Climb on the storage shelving to find a bag on top.
Checkpoint C. After you are ambushed and run across the rooftops, you will reach an area with two guards. Fight them, then go to the blue stairs and walkways. Go underneath them to find a bag hidden between the vents.
Chapter 1: Flight
Checkpoint A. When the mission begins, jump over to the first building. Jump over the electric fence. There is a building with a locked service entrance and satellite dish on top. Climb up on the building, and go to the dish. A bag is hidden between two vents.
Checkpoint C. While chased and shot by the helicopter, you will see an orange and white building to your right. Run around that building, and jump down onto the rooftop that follows (before jumping on the blue stairs). A bag is behind an air vent on this roof.
Checkpoint E. While running through the Centurian plaza, there is an open area that leads to train tracks. Go under the steps to the tracks, then turn left in the shadows. Climb over a fence to reach a bag.
Chapter 2: Jacknife
Checkpoint A. Go to the aqueduct when the level begins. While being chased by the helicopter, look for the Mirror's Edge logo to the left. Jump over to the left side, and go behind the blue and white pillars past the logo, immediately before the drain first arches towards the right. A bag is behind the pillar.
Checkpoint C. Run through the outside drain. Reach the top of the sewer area with large pillars close to each other. There will be two snipers on the right. Jump across from the platforms on the pillars, then jump to get the bag on one of the walkways next to the wall.
Checkpoint E. Use the pulley to raise yourself out of the circular drain area. Go to the orange container next to the forklift in front of you. A bag is next to the container to the right of the container.
Chapter 3: Heat
Checkpoint A. Enter the building, and go through the vent. Drop down to find a bag.
Checkpoint C. Climb up the pipes after the area with three heavily armored guards. Jump upwards, then across to the next building directly in front of you. This building has two red cranes on top of it. A bag is to the left, next to a chain fence.
Checkpoint D. You will eventually escape onto a crane. Jump down to a landing mat near a second crane. Jump to the ladder of the second crane from the landing mat. Climb up the second ladder on that crane to find a bag.
Chapter 4: Ropeburn
Checkpoint A. When the level begins, you will reach a rooftop with a lot of ventilation fans. Opposite this area is a building with a large "Duel" sign. A bag is to the right of the bottom of the "Duel" sign.
Checkpoint C. Drop down from the elevator after it crashes in the shaft. A guard will open a door. Run towards the wall, then climb up and over to find a bag nearby.
Checkpoint D. Run down the subway stairs, and navigate the platforms. Jump onto the tracks at the end on the right, and go up the ladder. Carefully swing on the bars, and do not fall off. Wall Run Jump onto the furthest bar, then swing onto the ledge. You will see the Mirror's Edge logo on the wall and two bars. Jump up onto one of the bars, then turn and jump up to the ledge that has a bag.
Chapter 5: New Eden
Checkpoint B. Climb up the long pipe, and jump to the nearby roof. There will be a yellow "Your 5-A Day" sign in front of you. Climb up onto the yellow and white building, then jump inside the area fenced in with barbed wire. A bag is between two vent blocks on the floor.
Checkpoint C. Swing from the two ropes while being shot at by two guards. Go to the front of the building with "Coronat Opus" on the side. Before going to the top of the water tank next to a locked door, you can get a bag next to two vent fans. Climb the fans' housing, then Wall Run over a camera to reach it.
Checkpoint C. Enter the plaza, and go through a vent. Drop down, and you will see the Mirror's Edge logo. The bag is on top of the parked van.
Chapter 6: Pirandello Kruger
Checkpoint A. When the level begins, jump up a floor. Run down the staircase. The Mirror's Edge logo will be at the bottom. Drop down onto another vent, then Wall Run across to another roof to find a bag.
Checkpoint B. Use the pulley to fall to the ground, then enter the warehouse area. Wall Run, then jump onto the vent to enter the office at the far end of the red walkways. A bag is on a shelf near the exit door.
Checkpoint C. Enter the next area to reach a second office. Go to the ground level, and jump over the fence. Run to your right past the forklift to the corner that is opposite from the pillar and locked door. Jump up to reach a gap in the shelving with a bag.
Chapter 7: The Boat
Checkpoint A. Go to ground level at the start of the level. Face the blue platform used to drop down from, with the white truck on your right. Find the forklift on the left, at the side of the warehouse. A bag is next to the warehouse next to a closed shutter opposite that forklift.
Checkpoint B. Enter the first green car parking garage. Defeat the guards, then go to the far left rear part of the garage, where there are two white trucks. Climb on to the truck to the right, then jump on the pipe, and climb onto the air vent. Continue around until you are at the corner where you jumped up from, but now on the other side of the vent. You cannot jump over the vent because you have climbed up; you must go around.
Checkpoint D. When reaching the outside deck of the ship, to your right is a dark room. A bag is in the corner on the ground.
Chapter 8: Kate
Checkpoint A. Make your way across the rooftops, and enter the first door. Walk down a short corridor, and enter the room. The Mirror's Edge logo is on the whiteboard. A bag is in the corner on your left, behind some boxes.
Checkpoint C. Use the elevator to go down to an open construction area. As you exit the corridor from the elevator, walk forward to the middle of this area. Look to your left to see yellow covers. There is a large white bundle with the Mirror's Edge logo on the side. Climb on top of the bundle, then jump up on the walkways. Turn to face the opposite side, jump, then turn and jump to reach the second level and a bag.
Checkpoint C. Get through the construction area, and enter the vent shaft. Continue along, then drop down, and walk ahead. A bag is on the left at the end.
Chapter 9: The Shard
Checkpoint A. You will enter a room which requires you to turn a gas valve. Ignore the valve, and instead go to the middle of that corridor. You will see the Mirror's Edge logo next to an area where you can Wall Jump up to. Wall Jump on the wall with the logo. You will find a bag as you climb up.
Checkpoint C. Immediately after Miller tells you to go to the roof, turn to your right, and run past the stairs. Use the red chair on the left to vault up to the platform with a bag.
Checkpoint D. Exit the elevator, and jump across to reach an area lit by orange lights. Enter the vent after the first area. Drop down from the vent, and find the Mirror's Edge logo. Wall Jump up above the logo to reach the bag.