Get All Weapons & Max Ammo
At the Plant Electrocution Level 2 slide down toward the holes in the ground and go in the 2nd hole. Make sure to glide into the hole and glide toward the lighted area. Pick up the items (key). Get the grapple and use it to get out of the hole and finish your slide. The key you got was for the door beside the vines behind the glass. Now go in and fight the plant man and get a envelope that has a 'C' on it. When you finish the game this will activate the cheats.
Envelope AGo to the Rooftop Battle level. When the clowns chase Mary, you will go up to the rooftops. Grapple hook up to her roof and beat up the white clown. Go up to the next roof, where you are on a little balcony. Jump across, then go in to see a thug run across a hall with the girl. Follow and he will jump off the roof. Follow, look down, and drop to lowest edge. Walk along to left until at the corner the grapple icon appears Grapple over, go in the door and pick up Envelope A.
Envelope BGo to the Bridge level. Knock out the thug at the start of the level. You should see the glowing item on the left when you start. Climb the ladder and jump/glide around the crate onto the other crate. Then, glide onto the platform with the letter.
Envelope CGo to the Plant Electrocution 2 level. You will start the Plant Electrocution 2 level by sliding down towards some holes in the ground. The second hole is not fatal. Fall into it and glide (to avoid minor damage). You will see a lit area. Glide down there and pick up the item you find inside. Use the grapnel to exit, jump out of the hole, and finish the slide. The item you picked up should be the key do the door right beside the vines behind the glass. Go inside and fight one of the "Plant Men". You will find an envelope that has a "C" on it in the room. When you finish the game, you can activate this cheat for all weapons and infinite ammunition.
Envelope DGo to the SWAT Chase level. You will enter the elevator shaft. Ride the elevator all the way down until it stops. Get off the elevator and wait for it to rise again. After it rises, jump down to the bottom and use first person mode to find the control box. Use a Batarang to disable it and the door behind it will open. Stay clear of the elevator and wait for the correct time to get in the open room. Inside the room is "Secret Key 2." Get out of the room and ride the elevator up to the top. At the top there is a door that is supposed to be locked. The key opens the door, and inside is an envelope with the letter "D" on it. Finish the game and the cheat will be unlocked.
Envelope EGo to the Gasworks level. You will reach a room with two levels, each floor with two goons on them. First, take out the goons. Then, look around on the lower floor until you see a sewer pipe with boxes in the sewage. Carefully glide down and land on the first box. Jump over the next few boxes and pick up the envelope with an "E" on it. Finish the game and the cheat will be unlocked.
Smoke bombsIn the level after the Batcave training, when you get to the area with a Joker thug, look around the big square. You will eventually find a ladder. Climb up the ladder, then look around for a box. Pick it up to get smoke bombs.
Flash bombsPress Action + Guard to use flash bombs. They cannot be selected in the gadget/first person view.
