This is a mess and looks like a ripped sprite cobbled together with a hand drawn shield by somebody who doesn't know what they are doing. Why is the minotaur sprite in a different resolution that has been resized and blurred?

Probably because, he scaled it to match the size of the shield. You need to use a (scale) filtering that goes well with pixel art.

Also link to the original art would be nice https://opengameart.org/content/animated-minotaur

Be nice.  Making skins that were cobbled together from ripped sprites/textures is how I got started in game development.

That said, this submission would probably be better served as a forum post asking for feedback/tips....such as proper scaling.

Scaled 2x with hqx

Just use no filtering at all (aka Nearest Neighbor). Also limit the pallete to remain the same as the original minotaur, and draw the shield using the same pixel size as the original. The end result would be seamless.