S - Fallout New Vegas, Fallout 1, Fallout 2 (Fallout 1 had the best pacing out of every fallout game, the world and the main story were very good written in a way so everything fit properly, fallout 2 downgraded in that regard but the gameplay and roleplaying aspects were just as good if not better, while fallout new vegas get the good parts of both games and mix them into one.)
A - Fallout 3 (Although the writing and world-building was dumbed down and the art direction was somehow worse than it's predecessors, and the combat was also terrible, it was fun for it's time, and kinda worked as a roleplaying game even if a lot of choices were just good, neutral or evil, let's also not forget that it was this game who revived the fallout franchise and without it there wouldn't be a fallout new vegas.)
B - Fallout 4 (Now this where things start getting bad, the writing and world-building was dumbed down even further, special stats barely mattered since you levelled up extremely fast and gained a perk per level, dialogue system got utterly ruined because they decided to copy mass effect's dialogue wheel in a pure open world game with a SHITTON of characters you can talk to, while mass effect's planets were designed in a more linear way, similiar to KOTOR I and II so they could actually polish and flesh out the dialogue more and make a voiced protagonist work in a RPG, like Gothic, while bethesda goes on their way to give every voice actor the lines in alphabethic order with no context whatsoever while also not bothering to check if the grammar is correct and if the audio files were properly edited, which is why their games have hilariously bad voice acting at times despite having great voice actors, the main quests were not very good written and were disappointingly short compared to NV's since they thought every player would do each faction's quests before choosing which one wins, power armor was both fixed and shitted on at the same time since they got the large and bulky feel from the first 2 games right, but retconned how their power supply works so you have to gather 40 fusion cores before using them to greatly decrease the risk of it shutting down mid-combat, and made them extremely unreliable by making each part get destroyed easily, leaving you in a naked power armor frame in a lot of fights where enemies have weapons stronger than pipe guns, not to mention how you can find that shit everywhere and get it in the first 5 minutes in-game on concord, removing the badass and rewarding feel you get when you get them in the previous games, the art direction was still shit, oh and they removed weapon condition, ammo types and the fucking skill system from every previous game, making you rely entirely on perks, the only reason the combat was mildly decent was because it was designed by ID Software, which is the company that INVENTED FPS games as a whole, and even then it was still not good because the engine was shit, they sacrificed weapon variety in favor of weapon modding, so you see the same 4 or 6 weapons over and over again but different mods, with a lot of them being copies of one another, like the combat rifle and the combat shotgun, that or having horrendous designs like the pipe guns and the "assault rifle", where as in 3 and NV there was a lot of weapons the player could choose and find from, the settlement system was cool but badly implemented, overall it's a cool and fun game if you manage to turn off your brain in several parts)
C - Fallout Tactics (Oh boy, roshambo was not wrong about this game, it was the first game that had a ton of retcons and lore breaks before bethesda came in, not to mention how it's not even an actually RPG, it was supposed to be xcom before xcom even existed apparently?, they decided to make the combat system from fallout 1 and 2 work in real time which was a terrible idea, the "tactics" in the tutorial are things i guarantee you that you're never going to actually use in missions, since every mission you just pick some squad members and make them annihilate everyone with burst or single fire alongside your character till you finish it, with some of the missions themselves being very broken, eventually the game got so boring and repetitive that i just uninstalled it
D - N/A
E- Fallout 76 and BoS (Do i really have to explain?)