This is our most comprehensive resource for searching and includes databases that you can't search individually. Start here, but use limiters to narrow down your search.
The best way to find criticisms may be to find books on the play and/or playwright.
Start in Polar, the ONU library catalog. There will be physical books and ebooks available. If you can't find what you need in Polar, search in OhioLink.
Depending on the play/playwright you may need to search for the title or the playwright.
Finding a clickable subject or author name will help narrow the search.