BioShock 2

To unlock the achievements you have to get a total of 18 stars. The third trial in each group gives you 3 stars, next group two and next one after that just 1 star.

Basic tips:
BEFORE YOU TAKE THE LITTLE SISTERS
- Destroy every healt-stations the enemy can use, mostly 2 of them on every match. You can buy med kits from the vending machines instead(hack them, so you can use less money on them).

- Go around the level, and use things that can help you(some levels has turrents e.t.c).
Note: Not every trail has turrents.

- Hack everything besides the healt-stations(these as told, you better destroy), this save time while engaged in combat with the splicers and stuff.

WHEN THE BATTLE IS ON
- On some "harder" trails, i found it easy just to spam around with cyclone traps around the little sister and just shoot the plasmid on the splicers.

- The thuggish splicers and other Alpha-daddy`s don`t go after the little sister. So focus on the others splicers like leadheads, houdinis, spider and nitro.

- If you need ammo, just remember to set up some traps around the little sisters. And to be on the safe side, always look on her when going to get ammo or other supplies from the vending machines.