When you are out of ammo but have a bench and several Power Nodes, you can refill the ammunition in a weapon to its new maximum by upgrading to a capacity node in that weapon. Note: This will also restore your health and help save medpacks.
Buy the Contact Gun as soon as possible. Ammo for it will start appearing around the ship. Sell all of the unneeded ammunition for it for 1,000 credits per unit.
Sell your Plasma Cutter at the store. It will fetch plenty of credits, but a new one is completely free. This is helpful for the max up challenge, because you can now buy about another seven nodes.
In Chapter 2, when you enter the Zero G Therapy area, there is a hole on the right side of the room along with debris blocking the hallway to other side and where you can see the planet. Once you go through the room on the left and get to the other side, back up to the debris. You can see something flashing outside in the direction of the planet--it is10,000 credits.
For every weapon you find during the game, there is a trophy awarded when you kill thirty enemies with that weapon. However, some weapons are weaker than others (for example, the flamethrower) and are much harder to complete. The easiest way to get these trophies is to find a Guardian (fat blob on the wall that shoots out pods) and kill its pods. Each pod counts as a kill, and it will keep re-spawning pods as long as you don't kill it. You can get all the thirty kill trophies from one Guardian as long as you have enough ammo.
Peng is located on the flight deck on Chapter 11. When in the flight room where your ship "used" to be, look between the walkways to notice the gap between Runway 1 and 2 by the shuttle in the Flight Hangar. You should see a very small statue that has a golden appearance. Pick it up with kinesis and you will receive the Peng treasure (and unlock the trophy). It can also be sold for 30,000 credits.
The Hunter is a regenerating Necromorph that is pretty much immortal. The first time you encounter him is tough and you just have to run. It is best to shoot off his legs because he does not regenerate them instantly. He is much slower without legs. Freeze him and he will be taken away. When facing him again in a later act, use the same strategy, then fry him with the rocket engines. Collect the Power Node that it drops.
Though huge, it is very easy to kill. Note: The following was done under the Medium difficulty setting. When the fight begins, notice that you are "caged in" by the Boss' tentacles. Shoot the yellow "blooms" around the Boss' mouth. However, upon shooting a couple of them, the boss grabs you, holding you in the air. During this time, it appears that you are helpless. Aim whatever weapon you are using at the time and shoot the yellow blooms. After a couple shots you will be dropped. The Boss will then start slamming its tentacles at you more frequently. They are very easy to avoid. Strafe left to right constantly. They will never hit you. The Boss will roar, shoot a few exploding cells at you, or will drop enemy pods upon you. This is part is also easy, considering it is usually only two small Necromorphs. After destroying the blooms, you will notice a "caged" area underneath the beast. Under this rib cage lies its many hearts. Again, use same strategy with the whole tentacle scenario. After a few times, the Boss will have his fit and open up again. Unload and the Boss will come tumbling down.
When there are tonsof dead human bodies around, stamp on them to decapitate some limbs. This prevents them from being turned into Necromorphs if one of the sting ray-like Necromorphs that brings them to life appears.
In Chapter 1, just after repairing the claw for the tram, hit your objective finder. Follow the blue line into the hall way where you need to go, then stop as soon as you enter the hallway and look up at the catwalk above your head. Ignore the alien for now. Proceed until you find the first corridor on the right. Walk into it there to see writing in an alien language all over. Look down there to see a message that says in English that reads "Don't listen to their lies, read what they're really saying." Continue reading to find a key that shows the alien language, and below that the corresponding are English letters from A to Z and 1 through 0. Although not everything will be legible, you should be able to decipher enough to understand what is written.
In Chapter 6, after you fight the final creature that spills the gas out, there is a dim flashing sign just before the anti-gravity area. This is a codex for some of the letters and all of the numbers in the alien language.
To slow down the regenerating hunter for the longest time possible, cut off all the limbs with the plasma cutter. Then, shoot the hunter with the stasis field (if it is charged). This will allow you to get around and away from it while focusing elsewhere.
To unlock New Game+, beat the game. Save and load your cleared save data. You'll start on the same difficulty, but with all your upgraded equipment, extra nodes, credits, and plans for the military suit.