Out of 52 titles Wired sent to Google, 16 have either been removed outright or re-released with more appropriate ratings and permissions. Mad Max Zombies is now the PEGI 12-rated Mad War Zombies, for instance. However, it's not clear just how many other titles have gone unaltered, and some offenders have over 100,000 installs.

We've asked Google if it can comment.

The presence of the disconcerting material may come down to Google's particular approach to app content ratings. While it's using the same content questionnaire as Nintendo's eShop and the Microsoft Store on Xbox (Apple has its own questionnaire and rating system), it doesn't really screen games in the way those companies do. It doesn't take much for a Play Store developer to fib about the suitability of a game and slip past concerned parents and content filters. Unless there's a stricter approach to verification in the future, you may have to double-check apps yourself before letting young ones play.