I've bought a game on Steam and completed 100% of the achievements for it a few months ago. However, I recently noticed that the number of achievements and perfect games hasn't updated on the 'Achievement Showcase' of my profile.
My best guess would be that this is due to the fact that the game in question (Lovers' Smiles) has a huge number of achievements compared to the amount of time it took me to complete them (100 achievements for barely 2 hours of playtime).
Why are some games excluded from the achievement showcase? Why do some games have achievements at all if they are not going to count towards the Achievement Showcase? Is there any way to tell before purchase if a game is in that situation?
Best Answer
Back on May 2017, Steam restricted the ability of newly released games to drop Trading Cards. Then on June 2018, Valve decided to restrict more features from newly released games, this time the restrictions being:
As per Valve's announcement, the games will be allowed to use this set of restricted features once the "confidence metric" goes up enough via player count and interaction. For the case of Lovers ' Smile, you can see that the game has a low number of reviews and a non existent player count, probably causing the game to never reach the "confidence metric".
As pointed out by Sinatr in the comments, you can see if the game has this set of features restricted by checking the features available in the game:
If the game has the restricted features enabled, the "Profile Features Limited" message will not appear: