If you go by playthroughs, it's teetering around the halfway mark. I ultimately DO finish every game that I start at some point, just not always on the first or second pass. Sometimes I just get this terrible sinking feeling as I reach the end. I get this hyperfocus fixation on the game loop and all of the different points of progress that I just don't want it to end. If that's how I feel, like I want there to be more game before I reach the end, I will often just restart and use whatever I learned to optimize and essentially have a more refined experience with the game. I've learned to like doing it that way, as it gets me more involved with mechanics I may otherwise pass over and thus, I ultimately get a more complete pass of the game.
Other times, I just get terrible choice blindness, where I can't decide what to plug into and cycle games day by day. I get into this ADHD mode where it's less about focusing on one specific thing and more about being able to quickly pivot across a lot of things. So I still enjoy it - I get these interesting side-by-side impressions of games and when I'm in that state, every game feels fresh and cool to me, even if I get antsy to play another not too long after. It's a bit like my mind is just changing channels. To continue is total boredom. Like, it's painful levels of boredom - dysphoric inner ennui. And 'poof!' goes my short-term memory and thus my ability to play the game competently. But if I move into a different game, I may zoom ahead like I've been practicing. If it's a game that I already have past experience with, it's like I never stopped playing it, and I'm just as into it as I was last time I started, if not more.
Just watching where my intuition pulls me, cues me into what I have state-dependent-memory for. This condition involves a lot of what might be called 'low-grade altered-states' that can arise. At this point in my progression, I can delineate them to an extent and tap into that state-dependent-memory to get really into a game really fast. It's basically maximum enjoyment and engagement in minimal time. And so, I tend to think that when I cycle, I am subconsciously seeking an 'in' to that. I just kind of let it lead me into playing that game that's going to be super captivating and interesting to me - leave a more memorable impression.
I'm just kind of riding the waves of a shifting mind with my playing habits, I suppose. I never force myself to finish games. Putting that weight on the playthrough, these tasks I must do... it kind of deflates the whole experience for me. I just kind of figure that whatever puts me in that semi-timeless flow state, is the right course of action. I can change goals at any time, as there is no consequence, so it becomes about what I simply find most stimulating at the time. That's how I tend to find the deepest niches with games I'll finish multiple times, even if I don't finish it every time. My brain seems to crawl meticulously over one or two major sections each time before it's had its fill. I feel that, too. I can tell what I'm training on and deliberately boost it, get a lot out of each time I sit and play. Something will just make me want to explore/analyze this or that thing about the game. Bite by bite, it culminates in this bigger picture that I recognize as unique to me. It's like this whole big experience that gets built across many scattered sessions and finished playthroughs. It can take me a very long time to fully appreciate just one game.