1. The movement in this game is best yet
2. The side quests are so well done that you can't figure out that you are doing a side quest, because it feels like a main quest but it doesn't advance the story. Plus keep an eye on your map, you'll be driving down the road and you'll see a little blue person icon. This icon is small side quests for you to complete, I've already done probably 10 of these and am 40% through the game.
3. Are you retarded? Hold/tap the run button - you can run while holding a rocket launcher even
4. My biggest gripe with the taking cover is sometimes the fucking doors wont stay open, but for the most part it works really well
5. Yeah the train stations I don't think get marked, but a lot of the restaurants don't get marked until you go their yourself the first time, then they'll stay on your map - more shit to find on your own - FTW