Has anybody heard about different difficulty levels?
Brink seems like a game that could throw some intense levels of difficulty at you or will it leave the hard modes in the challenge level option?

Nothing's been denied or confirmed yet, as far as I know, but I'm sure you'll be able to tweak the difficulty of the bots, at least offline.

There are difficulty levels for single player, it's been said a few times.

I do recall seeing the difficulty level in which the game developers were playing on as a demonstration, so yes.

Also the bots from Level 1-5 are easier to defeat than the ones from Level 6-10, 11-15 and 16-20.

Difficulty levels or not, you have lots of options at any given time, the high risk, high reward ones are like a higher difficulty level.

Link?