It's notoriously difficult to obtain mass data on videogames. While various surveillance tech makes the data easier to collect than it once was, it's proprietary stuff, for the most part. In the digital age, data is money, and publishers don't have a lot of incentive for sharing their profits and/or failures with others. For example, Kotaku did a piece early this year that showed just how damn difficult it is to pin down how much money is spent on an average blockbuster videogame. So while it's not particularly easy for the average user to find out certain facts about games on Steam--how many people have purchased it? What kind of sales bump happened when it was put on sale? Are some game types more susceptible to sale-boosted bumps than others?--what Valve does provide is the statistics for the achievements associated for each game. So you may not know how many people played game X, but you know what percentage of them got to point Y--as long as there's an achievement for doing so. I *think* the global achievement stats only take into account those who have installed and played the game at least once, but I'm not sure.
In the big scheme, this might not be indicative of much. Many games on Steam aren't only on Steam, and again, you still don't know how many users we're talking about. But it does give a nice indication on what particular subsets of Steam users are doing. Just for spits and wiggles, I thought I'd peruse my own Steam library, and note some achievement stats that interested me. Prediction: games are completed very rarely.
Binding of Isaac
*more than 50% of all players have defeated all the boss types in the basement.
*more than 25% have completed the game.
*more than 2.1% have reached 100% completion.
Given Binding of Isaac's reputation as a hard rogue-like, those numbers are all surprisingly high. I guess the game's of the sort that it's only played by people who like it, and most who like it play to a pretty high extent. Or I've gone into this underestimating what portion of people finish games.
*53% of the people who played the game finished it. (Tin soldier achievement)
*52.4% of the people who played the game finished it on the 1999 hard mode. (Auld Lang Syne achievement)
Compare that to the Kotaku report from a year ago that puts these numbers at 49.9 and 1.2, as of April 2013. That's a very interesting result, although less interesting than if we could measure how many more people added it since then. Still, it seems that a lot of people went back to the game to complete it again on the harder difficulty some time in the last year or so. That suggests the game has a lasting power that's a little surprising, given the complaints about how linear it was. The stats also illustrate that there's something to be gained by examining how they change over time. Conceivably, there could be a point where that 53% drops, although it doesn't seem very likely.
Following that Kotaku report, the next game they mention, Tomb Raider, *has* seen a drop in completion rate, currently standing at 49% rather than 50%. So more people have started playing Tomb Raider, but fewer have completed it. That makes sense; there's a little less impetus to complete a game after it starts to age. It suggests Tomb Raider has less a driving force than Bioshock Infinite, but that's not really a conclusion you can make until you've proven that there's a significant overlap in their respective user bases. Most of the lowest stats concern multiplayer achievements, which also makes a certain amount of sense--it's hardly a series known for its multiplayer play.
Since it's right near Tomb Raider, we'll go here.
*Beast Slayer I: Defeat Ordrak on Easy or Normal 16.1%
*Mod Squad: 1 game mod installed 16.5%
So more people have installed a mod for Torchlight than actually finished Torchlight. And the same number of people (0.03%) have completed the game on Hardcore Normal as on Hardcore Hard. And that number means that at least 10 000 people have installed the game to get the 0.03% value to begin with. At least the tormented (die 500 times) has 0.03% too. So at least most people playing the game aren't suffering excessively.
*Blaster: Bronze. Destroy 30 gems in a single move 66.6%
*Inferno: Bronze. Clear 50 Flame Gems 62.4%
*Blaster: Silver: Destroy 40 gems in a single move 60.1%
I have no idea what these mean. Never played the game. I guess it's reasonably easy to destroy 30+ gems, and clear those flame gems. I don't know why I picked this one. I don't have much to say. You might say I'm... running out of STEAM.
Yep, that's a note to go out on.