I'm working on a new game, it's a 2D tower defense game inspired by plants vs zombies. I'm almost finished with the coding for the towers behaviours and I'm going to work on the enemies soon, however I wanted to share the my prototype designs for the towers, I'm still not sure about the art style though, I wanted something simple but that allowed me for interisting tower designs, I also wanted something that would fit the style of the shaders I made for the characters and the background. Here are some of the sketches I made for the towers in-engine, with the character and background shaders.  

Here's a preview of the game in engine, I still need to add the enemy logic and a cooldoown for placing towers, but so far the shooting towers are working greatly!