Hints
NOTE: As their name suggests hints are not exactly BioShock cheats, and are usually just simple (but very useful) tips on how you can unlock secret level, features, find hidden areas and such. Hopefully these will make playing BioShock even more entertaining.

Achievements
Complete the following achievements to unlock Xbox Live Gamerscore points.

Completed Welcome (10 points): Successfully complete the Welcome To Rapture Level.
Maxed One Track (20 points): Purchased every slot in one of the Plasmid or Tonic tracks.
Maxed All Tracks (50 points): Purchased every slot in all four Plasmid and Tonic tracks.
Bought One Slot (5 points): Purchase one slot in any Plasmid or Tonic track.
Upgraded a Weapon (5 points): Acquire at least one weapon upgrade.
One Fully Upgraded Weapon (5 points): Fully upgrade one weapon.
Two Fully Upgraded Weapons (5 points): Fully upgrade two weapons.
Three Fully Upgraded Weapons (10 points): Fully upgrade three weapons.
Four Fully Upgraded Weapons (10 points): Fully upgrade four weapons.
Five Fully Upgraded Weapons (10 points): Fully upgrade five weapons.
Weapon Specialist (20 points): Acquire all upgrades for all weapons.
Fully Researched Thug Splicer (10 points): Fully research the Thuggish Splicer.
Fully Researched Gun Splicer (10 points): Fully research the Leadhead Splicer.
Fully Researched Spider Splicer (10 points): Fully research the Spider Splicer.
Fully Researched Houdini Splicer (10 points): Fully research the Houdini Splicer.
Fully Researched Nitro Splicer (10 points): Fully research the Nitro Splicer.
Fully Researched Rosie (10 points): Fully research the Rosie.
Fully Researched Bouncer (10 points): Fully research the Bouncer.
Fully Researched Little Sister (10 points): Fully research the Little Sister.
Prolific Photographer (5 points): Take at least one photo in every research group.
Research PhD (20 points): Max out all possible research.
Quality Research Photo (5 points): Take a Research Photo of the highest grade.
Researched a Splicer (5 points): Take at least one Research Photo of a Splicer.
One Successful Hack (5 points): Perform at least one successful hack.
Hacked a Security Bot (10 points): Successfully hack a security bot.
Hacked a Security Camera (10 points): Successfully hack a security camera.
Hacked a Turret (10 points): Successfully hack a turret.
Hacked a Vending Machine (10 points): Successfully hack a vending machine.
Hacked a Safe (10 points): Successfully hack a safe.
Skilled Hacker (40 points): Successfully complete 50 hacks.
Basic Inventor (5 points): Successfully invent at least one item.
Avid Inventor (10 points): Successfully invent at least 100 items.
Ammo Inventor (25 points): Successfully invented all possible ammo types.
Little Sister Savior (100 points): Complete the game without harvesting any Little Sisters.
Tonic Collector (50 points): Collect or Invent 53 Tonics in the Physical, Engineering and Combat tracks.
Historian (50 points): Find every audio diary.
Seriously Good At This (40 points): Complete the game on the hardest difficulty setting.
Dealt with every Little Sister (40 points): Either Harvest or Rescue every Little Sister in the game.
Lucky Winner (10 points): Hit the jackpot at a slot machine.
Toaster in the Tub (10 points): Shock an enemy in the water.

Additionally, there are ten secret achievements, all of which are currently unknown.

Unlockable: Good Ending / Bad Ending
There are two possible endings for BioShock that depend on how you treated little sisters throughout the game. If you choose to “harvest” more than one little sister, you will get the bad BioShock ending. If, however, you “harvest” no more than one little sister but “rescue” the others, you will get the good BioShock ending.

Big Daddy Battle
In order to do this, you need the Hypnotize Big Daddy Plasmid and the Natural Camouflage Tonic. All you have to do is use the Hypnotize Big Daddy Plasmid on a Big Daddy so that he thinks you’re a Little Sister and protects you. Now here’s the fun part - simply find and attack another Big Daddy and your Big Daddy will attack it to protect you.

Big Daddy Kills
When fighting a Big Daddy, use armor-piercing rounds, as they will deal considerable damage compared to regular rounds.

Sander Cohen’s Death
Sander Cohen will ask you to take four pictures for him to complete his masterpiece. After you do that, you can kill him at your convenience.

Security Drone Manipulation
Use a blast of the Electric Shock Plasmid to temporarily disable security drones before you do anything else in a room. Then, run up to them within five seconds and hack them! You can hack while the game is on virtual “pause.” You’ll have security drones on your side for the rest of the time you are in a fight after doing this.

Big Daddy Kills II
Once you get the Grenade Launcher and the Proximity Mines, this technique can be employed. Find a red fuel tank (all over the place), and cover it with about 6 Proximity Mines or so. Next, use Telekinesis to lift the massive explosive device and hurl it at a Big Daddy. This deals massive damage, leaving you with minimal effort to finish the job. Just be careful not to have the bomb blow up before you get there. (The launcher upgrade that deals no damage to you is a great thing to have just in case.)

Telekinesis Drop
While using the Telekinesis Plasmid, you can drop the item you are holding instead of throwing it across the room. To do this you must have an item currently being held. Pick up any item, with the Telekinesis Plasmid selected. Using the LT button, keep holding the item, and don’t let go of the LT button.

When you’re ready to drop the item, press the RB button to open your weapons menu, and in the transition of the weapons menu opening, let go of the LT button. Choose your weapon and the item will drop safely to your feet. If done correctly, the item falls at your feet, instead of being thrown, which makes the item easier to find when you need it.

PTTP Weapon Station Locations
Here are all 12 of the Power to the People stations locations. Remember, you can use each one only once.

1: Neptune’s Bounty - Freezer Bottom Floor
2: Arcadia - Tree Farm
3: Farmer’s Market - Winery Cellar Bottom Floor
4: Fort Frolic - Coctail Lounge
5: Fort Frolic - Eve’s Garden
6: Hephaestus - Across from Gatherer’s Garden
7: Hephaestus - Kyburz’s Office
8: Olympus Heights - Suchongs Apartment
9: Olympus Heights - Sanders Private Chambers
10: Apollo Square - Hestia 4th Floor
11: Pt. Promitheus - Atrium
12: Pt. Promitehus - Optimized Eugenics

Originally from ActionTrip