Chapter 2 - Dead Space 2
Chapter 2 starts as soon as you exit the vent. You'll find the first log of this chapter (Cut off Their Limbs) in front of the store. You also have access to the workbench nearby. Like what is suggested earlier, you must keep at least one Power Node with you always. For now, upgrade your Rig's HP. Don't worry later on as the upgrades you apply on this suit will be carried over to any new suits you'll don later on.
Two new weapons will be available as well. I suggest getting the Javelin Gun at least.
Exit the room then kill the pretentious necrom on the walkalator then loot the boxes nearby. There's a stasis pack in the dark corner right after the array of monitors. Up ahead is a locked room. Insert a Power Node to open it and grab the goodies inside, including the schematics for Power Node, text log (Quarterly Report), Ruby Semi-conductor and other items. There's also a nearby save point so backtrack to the store to register the Power Node and maybe purchase a few more. Sell the other stuff as well, especially the Ruby semi-conductor.
Save your game then head to the next hallway. You can unlock an achievement here, just refer to the video below to learn how to do it.
Achievement: Going for Distance
Grab the Power Node on the floor to the left, then kill the necroms that will attack you. Take the elevator nearby. After disembarking from the elevator and talking with Stross, head to the next area.
A necrom will jump on you so kill it. There's a halved acid necrom in the next room so take it out as well. Beware of another necrom that will appear in the corridor ahead. After that, head to the next area to find the laundry room. Take note that several slashers will attack you as the lights go out.
After getting rid of them, head to the next area. There's a text log (Titan Part 1) at the end of the short corridor and some items. Take the elevator down.
After getting off the elevator, use the save station nearby. There'll be a necrom that will spring in front of you from the vent to the right of the exit. Exit to the next area and you'll find a long corridor. There's a pretentious necrom on the floor so kill it to avoid getting damaged unnecessarily.
Continue to the end of the corridor but don't be appalled to discover the doors locked. (There's a Conduit Room here as well if you have access to it) You need to kill the wave of enemy suicide bombers that will come from the other side and one from behind you. Once the power is restored, continue forth.
After Isaac's dreadful vision and after reaching the tram platform, look down the tracks to the right to find the schematics for Stasis Pack. Search the platform for other items. Approach the tram's door and watch a flyer mutate a necrom in front of you. Kill them both, as well as the other one that will appear from behind. Enter the tram and hack the panel in the next car.
Schematics for Stasis Pack
As soon as the train starts to move, head to the next cars while taking out necroms along the way. Continue forth and you'll have a sequence where you'll need to jump to the next car. Do so until you successfully land there. Fight your way through again until the train derails and sends you sprawling on the floor. Finally, you'll be hanging upside down; take out the necroms that will attack you, and shoot the large one that will appear from the train itself. Completing this sequence unlocks an achievement and completes the current chapter.