Exacly, to get the Religious one you have to not shoot the guard, First time I did but died second time I let it play out and BAM! whole new quest line, Then in another quest I got a side mission from a new guy and F'd it up and well now not any more sidequests, from him, Honestly the design is fantastic.
The main quest and main side quests play mostly the same whatever your choices. The only half complex one is the one with Maelstrom gang, which is the only one they showed before release, like marketing does so well.
The game ending only has 3 different branches including 2 which finish the same with the same final boss, and that's only if you finished 2 other predefined linear side quest arcs (Panam's arc and Johnny's arc). Otherwise there's only a single ending, whatever happened before in your dozens of hours of game time.
Basically you may click or not on blue sentences and it doesn't change anything outside of flavor text. Clicking on yellow dialogue advance the story, mostly always in the same way. That's not really New Vegas level, and it's an old game now.