Hole.io vs Starve.io
Hole.io
Hole.io is an IO game where the sole objective is to suck as many things (or other players' smaller black holes) into your black hole just so you can grow it. The arena you'll be playing in is filled with plenty of buildings, moving vehicles, mailboxes, and trees that you can gobble up, but be careful! Other, larger black holes might go after you and gobble your black hole up instead! At the end of the day (there's a time limit), the player with the highest bulk, and hence, score, will win the game.Hole.io is pretty similar to Agar.io in many ways. However, you won't be able to eject your mass to propel your black hole forward. If this sounds like fun to you, you can check out the game for free on your browser!
Starve.io
Starve.io is a unique IO game mainly because it is more of a base-building and survival game rather than just a hack-and-slash arena. In this game, you will need to collect resources and turn them into useful items which will marginally improve your chances of survival. The crafting aspect of the game is very much simplified but it can still take you a while to figure out crucial crafting details like how much resources you need to create a certain item. Also, a quick tip if you will - grab as much food and wood as you can at the get-go.As a survival game, there are several important "meters" that you will need to keep an eye on, such as temperature and hydration. Hunger also something that you will need to frequently deal with, aside from other potentially hostile players as well as other monsters like vampires and zombies if you happen to play its other game modes. There is even a "hunger games" version which frankly feels a lot like a battle royale game.
Unlike many other IO games where players are always pitted against one another, Starve.io is a game in which you can actually choose to coexist with other players rather than just swinging whatever weapon you have in hand at anyone you see... though, many players still do that pretty often, especially those better-equipped ones.