In 1998, due to the content restrictions in Germany, Half-Life was added to a list of media that is prohibited from being sold. Valve had to create a special censored version of the game in order to release it in the country. You can read and learn more about the censorship on our wiki. According to German news website, Schnittberichte, 19 years after the game's release, Germany removed Half-Life from their list. This means Valve is now allowed to release the uncensored version of the game on their platform, Steam.