I'm relatively new to the game, but after blowing through my Mako in playthrough 1 and trying to milk XP the second playthrough, I noticed a glitch and I'm not sure if anyone has spotted this.
On the Xbox 360 version, when you're on an uncharted planet and survey a metal or recover an artifact, if you rapidly mash the a button after successfully completing the survey/recover, you can do it again for double the XP. At first I wasn't sure if it actually added the XP again or if it simply showed the little text box on the side, but I checked my XP before attempting it to verify, and sure enough it gave me double.
This even works when you disable the nuke in the Espionage Probe assignment; I finished disabling the last spot and immediately after it said the nuke was disabled, it brought the screen up again and I disabled the nuke... again.
This could just be my Xbox, but has anyone else seen this/want to verify my results?