Matching current art style is necessary. I am willing to see what you can do, but I will not put anything too much different in the game.
For example humanoid monsters / creatures usually have 4 frames of movement/run animation. Idle animation is usually only one sprite, attack animatins differs from monster to monster. Only exception is slime (the dark blueish blob), which is more fluid, but that is because of nature of the monster.
So lets see, what sticks and what does not, for now.
Also, we should communicate in a different way than here in the comments section. Twitter? Email?