I don't know what it is, but the struggle is real in regards to me, and marathoning games. For me this is the biggest embarrassment. I guess I don't feel I am a complete gamer until I actually marathon a game(A marathon to me is gaming for over 12 hours). Like I said I have been in the hobby for seven years, and I still haven't done it. There are reasons for it though.
First off the first three years in the hobby 95% of my Arcade/MAME time was focused on Donkey Kong, Donkey Kong Junior, and Donkey Kong 3. Unfortunately for me Donkey Kong, and Donkey Kong Junior only give out four guys, and Donkey Kong 3 while generous with men the first million, stops giving out men all together after one million. Having said that though, it's been three and a half years on other games, and I still haven't done it.
Right after the Donkey Kong series I played Moon Patrol, and Zaxxon. Again, games that don't continue to give out extra men. Then after that I decided to focus primarily on Nintendo Arcade games. One thing about Nintendo Arcade games though. Not a single one of their games can be marathoned. Well technically the Punch Out!! world record is a tad over 12 hours, but the game only gives out one man. Still I have tried games that can be marathoned, and there are reasons why I can't marathon a lot of them.
First is there are games that can't be played in MAME well.
Centipede-Track ball
Defender-too many buttons, needs to be played on Arcade
Missile Command- Track ball
Robotron-dual stick
Tron-unique stick
Then there are the games that create physical limitation.
Nibbler-The game is torture on my hands just playing several different times for an hour. I can't imagine playing it 12 or more hours. Also, I may have hit a wall with this games. Still maybe one day if I can break the final barrier, and I feel up to it.
Punch Out- Doesn't allow for bathroom breaks
Star Wars-Doesn't allow for bathroom breaks
Track N' Field-I just don't have the speed to marathon this game.
Then there are games I just have no clue what I'm doing. Perhaps an extended period of time would help on these games.
Joust-Lonnie makes it look so easy. The terydactyls get me, and I know there's a trick to them. Now if I put the settings to an extra man every 1,000 points, then yeah, I think I can marathon it, but TG settings, no way. I haven't given up hope on this one though.
Asteroids-I've tried the UFO hunter trick. That small ship just zaps me to no end. The small ship makes the game impossible for me.
Q*bert- I'm OK until the color constantly changes. Still I hold out hope for this one if I put serious time into it.
Tapper-I don't see how people can marathon this. The patrons are just too many, and too quick.
Then there are games where I admit I haven't spent enough time on at all to get a good feel on how I would do.
Frenzy
Gauntlet
Gyruss
Kicker
Mr. Do!
Pooyan
Star Castle
Super Pac-man
There is one game I feel that I could maybe marathon if I spent time save stating the sucker. That would be Timber. I got to 360k without save states, and so there is some hope.
Who knows maybe one day I marathon a game for more than 12 hours, but until then it's the one thing on my gaming resume that's a glaring personal negative for myself.