Can we judge the quality of a video game by the number of people who finish it? Probably not, since I've met many a people who just loooove Shadow of the Colossus and never reached the fourth Colossus. Nevertheless, that PC gaming service Steam allows us to determine which games people bother to finish.
Take BioShock Infinite, one of the best-reviewed games in years. If you finish it on any difficulty, ou earn an Achievement called "Tin Soldier." This morning, I checked Steam and—what do you know?—49.9% of Steam players got that Achievement.
Only 1.2% of Steam players got the "Auld Lang Syne" Achievement for finishing the game in the ultra-hard 1999 mode.
BioShock Infinite is only a couple of weeks old, so it's possible that the completion percentage will rise. But maybe getting half your players to finish your game is an achievement?
I checked the Achievements for the new Tomb Raider, which is a couple of weeks older than Infinite. The studio behind the Lara Croft reboot got 50.0% to finish their game.
But what if we go to games that people say were bad?
Aliens Colonial Marines, for example, which takes about five hours to finish? 42.7%.
The Walking Dead: Survival Instinct, which also takes about four and a half hours? Well, that game is in four acts. You get an Achievement for finishing the third act, and that Achievement has been attained by...27.1% of the game's Steam owners. Yikes. More evidence that it is, in fact, worse than Aliens!