1. Force The Batmobile Inside (Some) Militia Compounds
Later in the game if you're going for the full completion ending, you'll have to take out all the militia watchtowers, disarm all their bombs and - somewhat easier - beat the tar out of any foot soldiers taking up residence in the small zones across Gotham. For the most part it's pretty easy, but you'll come across a few encampments packed full of sentry guns, both big and small. You're supposed to upgrade the disruptor to a level where it can make these things backfire, but for some areas (particularly the zone underneath Poison Ivy's rather large plant), locate the nearby stairs, line up the Batmobile accordingly, fire the afterburner and it'll propel you inside where you can take care of the sentries no problem. This doesn't work for all the zones, but if you're finding in the late-game you've not allocated enough points into disruptor upgrades and don't fancy disarming all those bombs to do so, have a look around the world itself. There might just be a way to game the system slightly and force the Batmobile behind enemy lines. Are there any we've missed? Let us know in the comments what awesome, little-known features you've come across!