Hippo Supermarket is a merge game with a business wrapper: you combine identical items to produce higher-level ones, sell those for money, and use the money to expand the shop and unlock better stock.
The merge mechanic gives it a satisfying rhythm — every two items you own are a potential upgrade, so the board is constantly being tidied into something more valuable.
Drag one item onto another of the same type and level and they combine into the next level up, which sells for considerably more than the two parts.
Space. A full board can't merge, so storage and shop expansion do more for your income than unlocking new products.
Yes — drag to merge. Nothing to install.