Earlier this week Valve changed the way Steam's user reviews system works, in the process ensuring that only reviews from players who bought a game through Steam would contribute to the "Recent" and "Overall" user review scores that appear on the game's Steam page.

That means that players who acquired a Steam key for a game elsewhere won't be able to affect that game's Steam user review score, though they can still write and post reviews. Dev response has been mixed -- Steam user review scores can significantly influence someone's decision to buy a game, and many devs are left wondering what games will be caught in the crossfire of Valve's attempt to cut down on illegitimate Steam user reviews.

Now, Steam Spy developer Sergey Galyonkin has shed light on that issue by sharing a list of the (400+) games hit hardest by the Steam reviews shake-up.

Galyonkin claims that he's updated Steam Spy (an analytics platform which tracks publicly-available Steam data like game titles, owner counts and user reviews) to now track both a game's "classic" userscore and its new "Steam Purchasers" userscore, and some of the shifts evinced in his findings are striking.

IGF Award nominee Else Heart.Break(), for example, lost roughly 41 percent of its Steam user reviews in the shake-up -- and its overall review scores actually went up as a result.

By contrast, Steam Spy reports that Northway Games' and Radial Games' VR puzzler Fantastic Contraption saw its overall Steam review scores dip significantly this week as the game lost an estimated 97 percent of its Steam user reviews.

Galyonkin's full list is full of similarly interesting data, though of course any developer studying Steam Spy data should be aware of the platform's (self-professed) shortcomings.