Nothing. Not that I can tell.
I had a similar question. After a while of looking online and a bit of experimenting myself, I found nothing. I know that in LEGO Star Wars I-III and LEGO Indiana Jones it let you play as bonus characters in Free-Play mode. I knew for LEGO Batman It had to be different, as I tried multiple levels with empty hands. I was a bit frustrated while looking online, as many people who had never picked the game up but had experience with other LEGO games explained it unlocked bonus characters for Free-Play. It does nothing.
It let's You Use extra charcaters on certain levels
The armor plating makes the demolition suit bullet proof.
There currently isn't a Lego Batman 2, however a Lego Superheros game is said to be released later this year (2012).
type in goggle Lego batman cheat codes and find the code for min kit detector
beat the game
It let's You Use extra charcaters on certain levels
it puts in extra characters that you can be! cos i know these things :D
get the extra miniket detector and it will help find them for you
Yes, you can get Lego Batman for the PC.
There were no Lego Batman sets released in 2009. Lego discontinued the Batman sets after 2008.
LEGO Harry Potter! Duh!
Sadly, Lego Batman is not manufactured any more, however a great place to buy Lego Batman is Ebay.
you can get the lego batman bio suit and the lego robin bio suit in a new lego batman set released in 2013
The armor plating makes the demolition suit bullet proof.
nah
no he is only in lego batman 1
there should be because of the end of Lego batman 2