I can't give an exact count, but I'm about 99% sure my most replayed game is Home Alone 2 for Sega Genesis (unexpected I'm sure); it became a family Holiday tradition when I was a kid for me and my brother to take turns beating levels of the game on Christmas Eve, with me doing 1, 3, 5, and 7, and him doing 2, 4, 6, and 8. As an adult I have kept up the tradition by playing the game on Christmas Eve, though I don't do it every year anymore. I have no exact count to give, but I have definitely played it at least 14 times, though probably less than 20 times.
As for the rest of my list:
- My 2nd most replayed game is probably Sonic 3 and Knuckles, I also can't give an exact count there, but I've probably played it all the way through at least 12 times
- My 3rd is probably Halo 3 with at least 10 full playthroughs, I used to be in a Halo clan and helped run clanmates through the game on Legendary and helped them get all the skulls, so I played the campaign alot.
- My 3rd is probably a tie between Sonic CD and Pokemon Sapphire, with at least 7 full playthroughs
- My 4th is probably Sonic 2, with at least 6 playthroughs (though I don't recall ever beating the final boss, thanks to the no rings for that boss fight)
- My 5th is probably Age of Empires 2 with at least 5 full playthroughs
- My 6th is probably a tie between Halo 2, Saints Row 4, and Red Dead Redemption with 4 full playthroughs each