Cute game! And funny! I don't think picking out spelling mistakes is inherently fun, so adding the pixel art and timer to give it more interest was a great idea. I wonder if a more tactile player action would add to the fun? (like circling or underlining the words with a nice big red pen instead of simply clicking).
Love the pixel art (the teacher and the little sprites)! I was confused at first by the Eiffel Tower which shows up first - I thought it was an "A", as if it were the grade for the paper. But became immediately clear when the next paper showed up.
For future projects, spending some time on customising the button / UI themes instead of using the default adds an extra layer of polish (but I get it's also the type of thing that one can run out of time for in the end.)
Overall really charming game, nice work!