Limited myself to just one per franchise so its not all souls games…
1 (by a mile) Dark Souls 3. Ds1 probably had a greater impact on me because I’d never played anything like it at the time and it made me fall in love with games all over again. Still the only modern game franchise where you feel that utter exhilaration after each victory as you’ve really earned it.
2 Mass Effect 2. Probably the first time I ever felt like the story and writing of an rpg lived up to the quality of film and TV. Brilliant.
3 skyrim. I think that the years of reissues etc have left this to age fairly ungratefully and I think there’s a ‘over familiarity breeds contempt’ issue too. But if I think back to when I first played this, the scope and scale of the world (and the dragons!) made such an impact on me
4 Mario galaxy 2. Most fun I’ve ever had in multi player with my resolutely non gamer wife joining on these beautifully constructed levels.
5 bioshock. Best setting of any video game ever. Had me in raptures from my first play through.