You can't use the CTRL+V while on the review screen if you decide to give some feedback on the game.

For example, I wanted to review "PortaBoy" by Enchae with a custom font generated with Instafonts, but it won't paste what I wrote.

I wanted to write "Epic gamỉ͔͖̜͌ṇ̤͛̒̍ĝ̽̓̀͑ !" as the feedback message.