If I start playing a game, I usually keep playing it before moving on to something new. I don't generally get into new games or very many games at once and will go back and play old games I've beaten lots of times before. I don't typically abandon games midway through for the sake of a new game.

That said, for a long time I've been making runs at Neverwinter Nights over and over, never getting much past part 1 before petering out. A few months ago, I tried again and I think I'm near the end of part 4, much further than I've ever been before.

I almost gave up at the final boss of part 3 again because I was playing a dual wielding dragon disciple sorcerer. But managed to do it with some careful juggling of my battle strategy.

If I like a game, I'll sometimes casually engage in a 100% (or a mostly complete run of what is reasonable to accomplish. Dragon Quest 9 requires a huge number of grinding hours just for a chance at the top tier equipment, and there's dozens of the stuff in the game. You could grind just about forever in it.) But I didn't think you mean to include 100% runs in this finishing criteria.

If you did, I'm currently doing a (mostly) 100% run of Final Fantasy 12. And intend to do complete trophy runs of things like the Uncharted series and The Last Of Us. By playing them on the harder modes.

I suppose I began a playthrough of the Duck Tales remake, but since I was basically showing it to a friend of mine, I'm holding off until he wants to see more of it. I already played the NES version as a kid, and it seems to be identical in terms of gameplay.

There's probably a lot more games I'd want to do a 100% run for if I could think of them, but no others spring to mind.