This is quite unfortunate. I decided to go in to the app to look up spacechem. When I click search it comes up with random other games. If I didn't know it was on itch I'd have headed over to steam to get it.
The really confusing part is that proper search seems deliberately disabled. If I find "<form class="game_search" action="/search"><input placeholder="Search games & creators" required="required" name="q" class="search_input" type="text"></form>" in the web developer tools and remove "display: none" then I can just type "spacechem" in the box that appears and search just fine.