Really good idea, but lack of good type-ins makes some answers quite difficult. For example, "Symphony 9" or "9th Symphony" should work for Ode to Joy, as should Saint (or St) Matthew Passion, which is the correct title. Surely you can also accept the individual opera from the Ring Cycle, "Die Walküre" (or "The Valkyrie" in English). A couple of quick corrections, too: Carnival, not Carnaval, and it's just Messiah, not The Messiah. Fun quiz idea, though!
yes, nice quiz but, at least for the few ones I know, some type-ins were missing. "Le Quattro Stagioni" in Italian in case you want to add that as a type-in
Nice quiz! "Four Seasons" and "4 Seasons" both didn't work. I got it right after I added a "The" in front, but maybe those other answers could be allowed as type-ins? Holst's initials were GT (Gustav Theodore).