BioShock 2

This is just a simple boosting method to get the level achievements quicker.

1. Get a few other people who want to boost.
2. Play ADAM Grab (Not the team one)
3. Try to pick a level with at least 3 turrets (So up to 6 people may boost)
4. If you do not get a level with 3 then just have the 2 other players trade off on holding the little sister for points. (If you have 6 people.)
5. Get 2 people per turret.
6. Trade off hacking it for 10 points every 5 seconds-ish
7. Make sure everyone has Speed Hacker (Forgot what its called) to make it go by faster.

[EDIT:] If nobody touches the little sister everybody gets the bonus points for a win, because the game results in a equal tie.

If for whatever reason, you want to boost and you don't have Speed Hacker you could always boost w/o it. Yes, it will be slower but eventually you will unlock Speed Hacker and then you're all good.

GOOD LUCK!!!

Feel free to message me if anything was not clear enough.

Bioshock 2, Levels 1-20

Level 1- Beginning level, requires no ADAM and will unlock starter audio dairies, the winter blast, the shotgun, the pistol, and the electro bolt incinerate.
Level 2- Requires 500 ADAM and will unlock the machine gun, the maternal instinct, and staying visible.
Level 3- Requires 1000 ADAM and will unlock the security evasion and master researcher.
Level 4- Requires 2000 ADAM and will unlock Aero dash, and a bronze club membership.
Level 5- Requires 3000 ADAM and will give the pistol automatic upgrade and the “without a word”.
Level 6- Requires 4000 ADAM and will unlock the grenade launcher.
Level 7- Requires 5000 ADAM and will unlock the EVE saver and speedy recovery.
Level 8- Requires 6000 ADAM and will unlock the geyser trap.
Level 9- Requires 7000 ADAM and will give the shotgun rate of fire upgrade.
Level 10- Requires 9000 ADAM and will unlock the silver society membership and the crossbow.
Level 11- Requires 10500 ADAM and will unlock the backstabber.
Level 12- Requires 12000 ADAM and will unlock telekinesis.
Level 13- Requires 13500 ADAM and will give the tommy gun clip increase upgrade.
Level 14- Requires 15000 ADAM and will give the nail gun.
Level 15- Requires 16500 ADAM and will unlock the metabolic EVE.
Level 16- Requires 18000 ADAM and will give the Houdini Plasmid.
Level 17- Requires 19500 ADAM and will give the grenade launcher homing grenade upgrade.
Level 18- Requires 21000 ADAM and will give the elephant gun.
Level 19- Requires 22500 ADAM and will unlock sabotage.
Level 20- Requires 25500 ADAM and will unlock the insect swarm and the gold circle membership.

For the boosting with 6 people its obvious you need a map with at least 3 turrets. Here is a list of maps, appropriate for boosting:
- Arcadia (3 turrets)
- Mercury Suites (4 turrets)
- Neptune's Bounty (3 turrets)
- Point Prometheus (3 turrets)
- Hephaestus (2 turrets and 1 vending machine which can be hack without taking a damage)

List of maps, not appropriate for boosting:
- Farmer's Market (2 turrets)
- Fort Frolic (2 turrets)
- Home for the Poor (2 turrets)
- Medical Pavilion (2 turrets)
- Kashmir Restaurant (2 turrets)

All DLC maps are not good for the boosting, because all of them has 2 turrets and even less (Fontaine Fisheries has 1 turret)

P.S.: Also, use trials! Some trials on high level are very easy to complete (like 5-10 seconds) and give you a 1000 ADAM

UPD: JMJimmy says on comments:
"Most of the 2nd part of the list can be boosted in the same method as Hephaestus.
Fort Frolic = machine by the rocket turret
Farmer's Market = left of the rocket turret there's a vending machine beside a set of stairs that can be hacked
Kashmir Restaurant = Upstairs bathroom has a vending machine that can be hacked through the wall
etc

A bunch of the DLC maps also have vending machines that can be easily hacked (without using freeze method). Basically any vending machine that has a flat wall on the right side of it with enough room for 2 people can be done like the Fort Frolic."

>> Legit Little Moth achievement solution only <<

I think that the best way to obtain this achievement legit is to play Civil War how much as you can. Survival of the Fittest is much more frustrating and less effective, Capture the Sister takes too long. Others are much more less effective.
One Civil War match takes about 5-7 minutes, and you get at least 150 ADAM for completing each (if you aren't in the winning team) or 200 ADAM (if your team win tha match) even if you don't do anything else during this time.
You can easily gain about 350-500 ADAM if your stats are good (10 ADAM per each kill, photo, hack & vials, 50 ADAM for killing streak, 5 ADAM for kill assist, 100 ADAM for Big Daddy kill and 50 ADAM for each being Big Daddy) or much more if you complete some trials (additional 75-500 ADAM for each).
I'm level 42 now and I played for about 8 hours to level up to rank 20 (+ about 1 hour waiting/lobby time).
Level 20 needs to gain 25.500 ADAM total.

* If you want to leave a negative vote, please tell me why, so I can fix my solution if there are any mistakes in it.