Could be better. But try https://itch.io/search?q=mrdrn
It puts emphasis on word roots and word beginnings. And on words. And on projects. It is not a substring search.
Try
https://itch.io/search?q=mr+dr+nose
I works with relevance it seems. And mrdrnose has no relevance for the every day word nose. And drnose is not a word, so nothing could accumulate relevance for that one. And of course mr, dr, nose are three words, and mrdrnose is one word, relevant only to itself.
As for relevance and focus on projects, uhm, type v o i d in the search box. No enter.