I noticed a stealth-related gene tonic in BioShock 2, the Drill Lurker ("Quietens your footsteps and increases DAMAGE from melee attacks on UNAWARE opponents, especially with the DRILL swing").

Since the game does appear to have stealth mechanics, I would like to know how do they work: how does the enemy AI detect the player?

Specifically, I would like to know:

  • Do the sounds you make matter? (from weapon sounds, gunfire, plasmid/gene tonic effects to walking on different types of floor) Will crouch walking lessen sound?
  • Does sight or light levels matter? Can I lurk in the shadows? Sneak behind people? Hide behind objects? Being on a different level (a floor up or down)?
  • Once you're spotted, is hiding effective? Do enemies alert each other?
  • Any enemies with unique behavior when it comes to player detection?
  • Does difficulty matter?

Similar question of mine for BioShock 1: What stealth elements are there in BioShock?

  • 6
    How stealthy can you really be in a full metal diving suit and a drill for a hand? Jan 21, 2013 at 19:39
  • 4
    @DomenikVanBuskirk There's a gene tonic for that. A better question is: How stealthy can you really be when you're wearing a full metal diving suit and carrying an oversized drill, a machine gun, a grenade launcher, a bunch of other weapons, and a little girl on your back. Jan 22, 2013 at 3:26
  • 1
    Please at least do ask about one game at a time :)
    – badp
    Jan 26, 2013 at 15:37
  • @badp I just made the same question for BioShock 1 here. I initially asked about both BioShock 1 and 2, since I thought that the games have similar stealth mechanics. Jan 26, 2013 at 15:50
  • @LessPop_MoreFizz I disagree with that edit of yours. I am not "whining" about the downvotes. I am politely requesting for a comment on why they were cast, as I genuinely want to know the (what I hoped were helpful) reasons behind them, so I could improve the question or address the concern. That request was posted after this question initially accrued downvotes (more than one, not single like you mentioned). Jan 27, 2013 at 4:14

2 Answers 2


From what I known from playing Bioshock 2 as stealthy as possible:

  1. You will get sneak bonus if you manage to kill the enemy unalarmed (which are unseen, quietly, no bell alert ringing etc)
  2. Enemy will react to sound, especially gunshots and bell alert. But before they can hunt you down, they must seek you first
  3. Different surface will produce different level of sound, so stealth while on a pool of water = not good
  4. Crouching and darkness/shadows will improve stealth.
  5. You can indeed sneak up enemies from their back, as long as they don't turn their head around
  6. Hiding from a different floor level works (exp. you on the 2nd floor, bad guys below the stairs) but watch out for noises (walking, grinning with your drill etc)
  7. Alerted enemy will hunt you down for a period of time before they continue their routine. They will also alert each other and will search for your at the last spot they thought you were
  8. Stealth killing enemy near another enemy WILL alert them although they don't see you (because of the noise)

I don't know about changing game difficulty will or will not affect detection BUT anything I told you doesn't really matter TBH because once you're spotted, gunning them down is way easier than run and hide. Honestly this game is a shooting game and stealth is not a way to enjoy it.

  • "You will get sneak bonus if you manage to kill the enemy unalarmed" Does this happen even without the Drill Lurker gene tonic equipped? Jan 25, 2013 at 10:18
  • According to the tonic's description, if you don't equip Drill Lurker tonic then you'll get normal attack damage so without tonic, you'll just killing enemy ninja style without any advantage Jan 25, 2013 at 10:30
  • @Samir Not sure if quoting because it actually was funny, or because you actually can be stealthy >.> Jan 25, 2013 at 14:03

In addition to (and contrary to some points of) this other answer, and from my experience:

  • Enemies will only react to weapon sounds if you are near them. I have used the spear gun from a far location and occasionally missed enemies by a few inches and hit wall or objects near the enemy. They never noticed that they're being shot at (probably because of the distance).

  • Surface is not a factor in sneaking. The speed of your walking is more of a factor (you are less likely to be noticed if you're walking slowly or crouch-walking).

  • Shadows or light levels do not seem to be a factor at all.

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