On Roblox, old and new coexist. It’s an interesting manifestation of the company’s ethos, and one reflected in the decisions Roblox makes with its underlying technology.

Roblox shares slid more than 20% in early trading, as the gaming giant dialed back its forecasts for growth and first-quarter earnings showed player spending is slowing.

The gaming platform Roblox is working to expand its base of older users and is turning to artificial intelligence and traditional gaming consoles to do it. At WSJ’s Tech Live, Roblox CEO Dave ...