Kingdom Rush Online is a tower-defense strategy game with 2D cartoon medieval characters. Calling an early wave gives bonus cash and reduces spell cooldowns a bit. Try to defeat all waves of enemies at all levels, and challenge four difficulties of each level. Use the skills to help defend the kingdom!
https://www.bestgames.com/games/Kingdom-Rush-Online/index.html
Tap the construction area to open the building list and select the towers
https://www.bestgames.com/games/Kingdom-Rush-Online/index.html