Most engrossing video games you have played?

I could put hundreds of hours into the Halo franchise, perfecting my game. I find everyone ends up with a signature couple of weapons. I loved the sword, shotgun and rocket, battle rifle too. I got so precise with a rocket I could kill someone standing right in front of me. You have to think in area of effect. I love the Fallout franchise. One of the best things about it, I think, is collecting things. Prewar books, decent food and water, weapons and outfits. I loved Elder Scrolls, Skyrim. Perfecting my sneaking and assassination skills was my favorite aspects of that. A sneaking bowshow was devastating and avoided annoying reprisals from guards.