I tend to give all games the full two-hours (or until they’re completed). But I don’t think there’s anything at all wrong with saying “I disliked this game so much that I stopped playing.” That’s a valid reaction.
Sometimes if I force myself to play a game I dislike my feelings can harden against it. But other times the game has an impressive ending or I didn’t understand what genre or style the game is so it turns out to be worthwhile to finish it.
If you spend half an hour on a game but don’t get in to it. You could try again later.
According to the rules, judges are required to score at fewest five entries. That’s five out of fifty-eight this year. As a judge, you’re not obligated to give scores to every game you play. If after ten minutes you can’t stand something, just quit and move on. If you feel guilty about not playing the work in question all the way though, then just don’t score it.
However, it is your right as a judge to judge (within the rules) based on your criteria. If some other judges don’t agree, that’s the whole point, isn’t it?
If I don’t want to continue on a game, then I don’t. The onus is on the game to convince me to stay.
With over fifty games, there’s no way I’ll get to all of them. If I grind cycles on a game I’m not enjoying - whether because I’m stuck, repulsed, or just bored - then I’m going to get to fewer games, both because of time spent and because I’m less likely to continue on the IFComp games as a whole.
Note that I take this attitude with IFComp specifically because there are so many games. In a smaller competition format, I would be more patient.