Walk through the Cassini Towers and wait until Isaac has another "freakout" in the little girl's room. When it ends, walk to the dresser to the right to find 1,500 credits under the stuffed teddy bear.
Complete Dead Space: Ignition in single-player Ignition mode to unlock the Hacker suit, a Hacker-themed Contact Beam weapon skin, exclusive audio logs, and extra power nodes, health packs, and credits.
In Chapter 7, right after Isaac starts the elevator to go to the Solar Array area, a group of Tripods will appear. Use the Detonator to shoot them. Hitting a Tripod with the Detonator anywhere on the body usually knocks it off. Use Stasis to hold a Tripod in place when more than one of them appears. Knock off all Tripods in this sequence to unlock the trophy.
Complete Campaign mode to unlock the Hardcore difficulty setting. This mode only allows you to restart from the last save game and only three save slots for the entire campaign will be available. You also cannot start this difficulty from the "New Game +" option.
To get unlimited credits, purchase the Supernova or Martial Law downloadable content. Go to the store and purchase the Detonator weapon for free. Fire the mines at a wall, then deactivate them and collect them. Do not reload the Detonator. Sell the mines and Detonator for credits at the store. Buy the Detonator back for free and it will be fully stocked. Repeat as desired.
Complete the game under the Hardcore difficulty setting and upgrade the plasma pistol. Go to the first shop to find the one hit kill hand cannon. This weapon resembles a foam finger, and when fired Isaac makes "Bang Bang" and "Pew Pew Pew" sounds.
Find the following schematics in the corresponding locations:
Force Energy: When you reach the zero gravity area, go to the lower level to find it on the ground.
Advanced Suit: Enter the locked room opposite of the detonator mines trap. The schematic is inside this room, but you need a Power Node to open this locked room.
Contact Energy: In the zero gravity station where you move the lasers to gain access to the shaft that leads inside, look outside from the inside of the shaft to find it.
Hacker Suit: Found at the end of the tram walkway area, near the location you encounter the Fire Sack Necromorphs.
Power Node: Found in the first Power Node locked room you find. You can open the locked door with a Power Node. One can be found on the ground through the door to the left of the closet.
Stasis Pack: Found on the tracks by where the flaming train passes you for the first time.
Javelin Spears: Found behind the big marker statue towards the windows on the left.
Pulse Rifle: Once you are out of the train, it is in a corner just behind where the train is hanging.
Security Suit: Found on the top shelf of the room just past the door that you must slow down to walk through.
Detonator: Found in a room at the top of the church by the save station.
Line Gun Ammo: After crawling through the duct and falling, you will go through a storage room. You will find it behind some shelves on the right side.
Medium Health Pack: After turning off the gravity and going through the holes in the ceiling, it will be floating in the middle of the room.
Ripper: In the multi level room, ride the elevator down, then go to the right side of the room.
Flame Thrower: After you exit the gym, follow the path and go into the classroom to find the "Kids Gone Crazy" text log. In that same room, there is a smaller room on the right side with blood on the wall. The schematic is on the ground.
Pulse Rounds: When you first meet Ellie, she will unlock the gate. Instead of going through the gate behind her, follow the path around to the right where it is blocked by debris
Seeker Rifle: On the path at the start of the chapter, enter the door to the right. You will be on a balcony and the schematic will be on the far right side on the ground.
Contact Beam: The schematic is in the locked closet to the left of the location where you first see the save station on the wall. Use a Power Node to open the closet and get it.
Force Gun: After you exit the elevator, turn left. You will find some yellow lockers. The schematic in the second locker from the left.
Ripper Blades: At the start of the chapter when you enter zero gravity, the schematic will be floating at the bottom of the room.
Detonator Mines: When you first talk to Ellie and Stross, go to the next room, and take a left. The schematic is beside a body.
Large Med Pack: Found in the room where you first meet Ellie. It is located past the table in the corner. Use kinesis to move the table.
Vintage Suit: Found in the first locked door in this chapter.
Flame Fuel: When you encounter the laser traps, take a right from where they were located. You will see a few crates lying around. Use kinesis to move them to find the schematic and an audio log.
Seeker Shells: Found behind the guardian mounted near the exit door of the room where you fight Stalkers and Cysts.
In Chapter 7, find the mainframe room where ANTI is located. The circuit room that is to the left (when ANTI's hologram emitters are behind Isaac) has breakers that also turn blue, as well as green or red. Insert the four breakers in that circuit room to change them to blue. Follow the access tunnel to reach Peng's Treasure.
In Chapter 15, go to the final room where there is a store and save point. Then, go back down the corridor and enter the room with the two power nodes, a Ruby Semiconductor and some other items. Collect all of the items and return to the save point. Save the game, the reload it. Go back to the locked Node room and the items will be there again. Collect them again and repeat this as desired. You can also do this in chapters 6 & 7.
Note: This only affects the current level. Exit to the main menu and return to the level. You can use the the weapon loadout screen to change weapons. You will resume with the default ammo for that weapon. Note: You can only select the left special weapon; the other two special weapons are deleted from your inventory.
Find the mainframe room where ANTI is located. The circuit room that is to the left has breakers that also turn blue in addition to green or red. Insert the four breakers in that circuit room to change them to blue. Follow the access tunnel to reach Peng's Treasure.