This game had a LOT of potential, but just has so many frustrating moments...
Saving: You forget to save and guess what, you have to start ALL OVER! No auto-save or instant save features.
Time-limit: I also dislike the time limit. I understand that the initial reason was to make the game more engaging, however this doesn't work for me. I would just like to do the side missions without having to worry about the oh so frustrating time limit. Without the time limit this game could have been kind of similar to GTA.
Missions: Another thing that frustrates me is how you enter a mission. You all of a sudden enter a mission while you are WAY OFF the actual icon on the map and were just passing through.
Way points: Why can't we set a way point on our map?
These are just a few examples the developers could have easily implemented, but just didn't for some selfish reason. It looks like the developers only concentrated on the feature to combine weapons, which is fun for an hour or two at most...