Hello so my friend Szczerus made some arts and wanted to judge
So go ahead

it looks too flat,
cartoon - not always mean shadeless,

proper cell shading can imrove those images alot.
also poses too simple. mirrored sides, same line thickness everywhere,

heres alot of things to focus, but every artist starts from crap, so
i can just wish a good luck to your friend and keep drawing more = having lvl ups.