Shark.io

Shark.io ties boost directly to a resource you have to actively collect, white objects scattered through the water fill the meter that lets you burst past rivals, which means positioning near a cluster of pickups matters as much as chasing any single opponent.

Because boost is what decides most close encounters, saving a full meter for the moment a smaller target is actually within reach tends to convert more chases into kills than burning boost early and coasting in on regular speed. Skins and transformations are cosmetic, but a distinctive one can make it harder for rivals to judge your exact size at a glance, a small edge worth factoring in during a crowded fight. EvoWorld.io runs a similar grow-and-hunt food chain with evolving creatures instead of a single shark.