I'm in the middle of playing my first game, and having a good time so far.

But the various barriers that block the sections off from one another (in the campaign at least) threw me for a massive loop: at first I went around them with a boat; this led me to discover that you can't interact with the barriers at all if you approach them from whatever side is the opposite from the one the game expects you to be coming from.

This is very strange.  Until I realized I had to approach from the other side I had no idea how I could get open them,  or that interacting with them was even a possibility.  Then, after I had the Passport to get through the Garrison, I tried opening it from the "back" side and nothing happened.  Finally I realized that you had to be on a certain side (whatever side the campaign expects  you to be coming from) to interact with them.

Just giving a shout here to anyone who might be stuck like I was; also, this is an issue the devs may want to fix, since it's pretty off-putting to anyone just starting the game.