Can't Find The Bomb
In 'Cursed', Artyom is tasked with destroying the tunnel and airlock where the nosalises (mutants) are spawning from.
Position yourself so Khan and the defenders are behind you for the following directions:
The bombs are at the end of the right tunnel.
Destroy the left tunnel by "using" the glowing bomb hologram on the tunnel supports at the dead end.
Destroy the airlock by going up the stairs and using the bomb holographic on the supports. The stairs are to your right (and a little forward), if you are standing with Khan and the defenders at the station's entrance.
Extend Your Filter
Keep from sprinting and jumping as much as possible or and your filter will last much longer.
Free Nightvision Goggles
If you didn't purchase the Sneaking Suit at Armory Station, the earliest you can get a pair of Nightvision Goggles will be in Front Lines.
Once you have control over Artyom, turn around and follow the train tracks. Two enemy soldiers will be next to a red breaker box holding this piece of equipment.
(Note: while you can complete the game without the NVG, there will be several more instances when these items appear in plain sight in later stages).
Moral Choice Indicator
While there are obvious moral choices in the game (where both decisions are obvious), there are more subtle moral choices that will determine which ending (just two) you get at the end.
When choosing an action, the game world will temporarily flicker with a rust-ochre color (and you will hear faint murmuring) if you made a moral choice (good or bad).
Preventing Accidental Ammo Discharges Hand Over Fist
When pumping the Tihar (Pellet Gun) or the Hilsing (Spear Gun), you can accidentally discharge ammunition when the animation resets to "fire mode" (because the primary fire button or Right Trigger also works the air pump).
Apparently, the game doesn't tell you the Alternate Fire (or Precision Aim) also works the air lever. If you use the Alt.Fire or Left Trigger to work the air pump, you will not accidentally discharge any ammunition until you are ready (the Tihar and Hilsing only have aim-down-sight for secondary fire).
S.T.A.L.K.E.R. Series References
When in the Library, the two rangers will announce the titles of several books. One of them is "Roadside Picnic" (1977) by the Strugatsky brothers, which was the book that Andrei Tarkovsky's 1979 movie "STALKER" was based on, which then was the inspiration behind S.T.A.L.K.E.R. Shadow Of Chernobyl.
The first person you can talk to resembles a "loner" Stalker and says "Take it easy bro!"
The scene with the campfire with the guitar.
The winter mask that are on dead people.
Before getting into the train car at Armory Station, you can purchase a Stealth Suit for 100 military cartridges from the vendor across from the Ammo Exchange. There is a vendor next to that one that sells an Armor Suit that decreases damage. Both suits can be worn simultaneously. A similar Armor Suit is also sold by a vendor next to the Ammo Exchange in Polis.