Haha, I love that aesthetically it's a standard space shooter, but then also you're a cow. Er sorry, an Ox lol.
I really like the formation changing in concept, however I'll confess I'm struggling a bit to grasp how to actually utilize it effectively. In your playtesting, did you regularly change formation and spacing, or did you find you just settled into one or two that you liked? To an extent I can see how spacing makes a difference, but I'm not sure if the advantages/disadvantages of V formation versus O formation are apparent to me, for example.
Then again, I've never been very good at sidescrolling space shooters, but this is both creative and really cool, well done!