Bloons Tower Defense 6

Bloons Tower Defense, or BTD6, is a game where you use towers in the for of different monkeys to pop balloons and clear different levels. It uses a wave system, so each wave will be stronger than the last, so you need to use cash from popping bloons to upgrade your monkeys to make them stronger. There are different types of towers, each with different synergies and abilities. There are also different types of balloons, such as lead, camo, and purple, which each are invincible to specific types of monkeys, forcing you to choose carefully which monkeys you are going to use. Each monkey has 3 different upgrade paths, so you can mix and match how you want each one to work. You can collect achievements, earn medals, collect new skins or cosmetics, or complete quests to get new rewards. It is also multiplayer on steam, so you can play with up to 3 other friends in 4 player co-op.