Hilarious in Hindsight: Being written by huge anime fans, Steven Universe would include the concept of a "Kindergarten" wherein alien Gems are "born" through coming out of holes embedded in the mountains shaped like themselves. This lead to gems like this gif◊.
The silhouettes of people include perfect replications of their hairstyles.
It's slowly coming this way!
There is a sound effect for "glance".
The story is made for people with a very specific combination of fears. If you don't have those fears, the entire comic is nothing but ridiculous.
If you watched Steven Universe before reading this, there is 0% chance you didn't think about Kintergardens and corrupted gems emerging from the holes, making it harder to get spooked. See above. (Though if you read and were frightened by the manga before watching Steven Universe, the opposite likely happened - making the Kindergartens much creepier!)
Viewer Gender Confusion: Owaki is male with a somewhat female face and feminine haircut. You would think Owaki and Yoshida are lesbians up until his dream where he is a caveman with a stubble or when he enters his hole.