The characters were so fun. Loved the designs and the thought that went into their weapons, especially with the mushrooms XD. The sound effects worked well overall, especially for the guitar. I think mechanically the shooting felt nice with using the mouse to aim and shoot, as well.
It took a little to get used to the isometric layout, but that might just be my own biases. I did find it tricky to figure out what the special abilities did at first, though, with the exception of the mushroom bombs. Having more visual feedback might work well there, like a cloud of smoke for the machine gunner that appears around her where the mouse is pointing.
Great job! :D