Yup. There is no reason for mixels here. Also it is full of artifact colours. https://www.linneart.com/pj/?input=https%3A%2F%2Fpixeljoint.com%2Fpixelart%2F158313.htm
I'd ask you to use pixels of the same size, it's the law here, and your piece might get "revision needed" status
hahah many thanks!