Same as Jugan0, I killed every ufo and nothing happened and the controls are a bit tricked. That's some steriod cow! But I like the idea and the sound is cool! You could add something to indicate that fellow cows are being abducted to force the player to move from one ufo to the next before completely destorying the first.

Really cool concept! Killing UFOS was really satisfying, that was well done.
I think a tutorial, even in the game page, would add a lot. I destroyed every UFO in the first level and collected every gem, yet nothing happened afterwards and I don't know if that was the end of the game or if I am doing something wrong. The art was very fitting, and your concept is great. I think with a little tweaking of the player movement to be easier to control and some more content this would be a really great entry. I think this concept could also work really well as a game where you kill waves of UFOs as a cow, as most of the gameplay is the combat and that is definitely the most satisfying part. Great job on the game, I had fun!

Ahah, love the idea of the revenge !

Also, good pixel art ! Just need a victory screen and a menu :)