Y (Before you say that Y saying "i" is incorrect, note that it's actually the word "y" in Spanish meaning "and".)
Credit to @JoetheScratchMaker for voicing Y, @Nguyen_CLS_Noolish (even though he's a bad user) for voicing D, E, I, X, and W, @LogoFan2016 for voicing U, @ThreeTenThirty for voicing Q and V, and @ItsWinktheWolf for voicing F. I voiced A, L, N, and R. Credit to @PhonicLover44 for the letter sprites. Credit to @elithepidude for the gem sprites. Wobble, button push, and splat sound effects from Envato Elements S splatting sound and explosion sound effect from Mixkit First boing sound effect from myinstants.com Goop sound effects from Soundbible I made the hit, shaking, door, and alarm sound effects by myself. Credit to Mike Salcedo for Alphabet Lore.