As gaming hits draw tens of millions of simultaneous players, Roblox engineers make sure the internet’s youth never deal with buffering.

A 16-year-old’s Roblox game, Grow a Garden, has shattered records for the most concurrent players in history.

In most Roblox games, your character is, well, just a block. But in Dress to Impress, users play as a highly customizable model, which appeals to the fashion-obsessed.

Whether it serves as a chill escape from the onslaught of the real world or simply a way to beat vacation doldrums, a viral ...