I just recently started playing bio shock and it was really hard to kill "mr. bubbles" . 
Edit: just tempered having to kill 343 :c
What enemies do you have a hard time killing ?  
[spoiler]Wake up Mr. Bubbles ![/spoiler]
						
					
					
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	This guy is not a bad guy...but the guy that helps you in dark souls at the start of the game you who gives you your stuff...well i may have killed him... [spoiler]oops :([/spoiler]