I recently tried bloonstd.net and was pleasantly surprised by how smooth and fun the gameplay is. It’s browser-based (no install needed), so I could jump right in. The tower defense mechanics are simple but strategic, and the graphics are bright and engaging.
There’s a good variety of towers to experiment with—and it’s all free to play. https://bloonstd.net also supports both desktop and mobile controls, which is a plus. If you enjoy casual strategy games that don’t require heavy setup, I’d definitely recommend giving this one a go.