As I've been playing through Deus Ex, I've seen my fair share of messages pop up, informing me that I have earned XP, but because there's no explanation for the message, It's not always obvious what I've done to earn the XP in the first place.
For instance, it took me a while to realize I was getting the "Marksman" bonus whenever I shot someone in the head, instead of tranq-ing them in the torso. Some others I've seen a lot, but still don't know what caused them — "Traveler", and "Expedient", for instance.
What actions (or suite of actions) in DE:HR result in an XP Bonus?
Best Answer
Aside from completing objectives (primary objectives earn 1000, 1750, or 2500 XP; secondary earn 500 or 750 XP; side quest bonuses earn 100, 300, or 750 XP) and the two mission bonuses of Ghost (500 XP) for getting through an area without ever being spotted by an enemy NPC and Smooth Operator (250 XP) for getting through an area without setting off any alarms, XP awards are divided as follows:
Combat Bonuses
Hacking Bonuses
Exploration Bonuses
The following bonuses are all tied to entering secret areas, but the actual mechanics determining how one is awarded rather than another is still unclear to me.
Miscellaneous Bonuses
(This information was adapted from Absolute Steve's FAQ on DE:HR on GameFAQs.)