Graphics are a lot of fun. I liked the concept of deploying your fighting sheep on specific spots to control the invasion. Couldn't beat the second level though as I would get easily overrun.
If you were to develop it further, a tutorial level/screen would be super helpful to explain the attributes of each sheep. I found it a bit overwhelming to get the choice of changing the amount of each type of sheep before the first level. Also it would be nice to see some way for the sheep to recover their health/wool while they're kept in the base so that they could fight again later.
Good job!