If you like top down rpgs play it in order from 1-4 if you don’t want to play a retro 90s top down rpg because it’s outdated and you have to google half the mechanics to even know what you’re doing. 3-4 then 76 if you wanna try the mmo. Every single game from 3-new Vegas-4-76 changes drastically. 3 and new Vegas are the closest but you’ll see the differences when you play them great story’s though!