One significant change in the new Roman Missal is that the familiar acclamation “Christ has died. Christ is risen. Christ will come again” will no longer be used as an acclamation to the Mystery of Faith. The reason for this is that the three options given for the acclamation are all addressed to the Lord (e.g., “We proclaim your Death, O Lord…”). They all note our relationship to Christ’s Paschal Mystery (“When we eat this Bread and drink this Cup, we proclaim your death, O Lord…”). The acclamation “Christ has died…” does not follow this form; so it was not included in the options.
And you know, it makes sense. Yes, I understand that this is a favorite proclamation, but do remember that it's a proclamation, not an acclamation! Why on earth, when the Lord Jesus, Body, Blood, Soul, and Divinity, is right here, right now, live and in Person, is present—really present!—right here with us, would we speak about Him as if He'd left the room?
It's a beautiful statement of our faith, and I do urge you to say it right out loud or in your hearts while you're walking down the street, driving, whenever...but not when Jesus is right here with you. Talk to Him...not about Him.
Also, instead of directing us to give the acclamation (“Let us proclaim…”), the priest will simply announce, “The Mystery of Faith,” acknowledging the reality that our acclamation is something that wells up, without needing to be asked for.
The last noticeable change in the Liturgy of the Eucharist will be the invitation and response to Holy Communion. The priest will say, “Behold the Lamb of God. Behold him who takes away the sins of the world. Blessed are those called to the supper of the Lamb.” There are two key allusions to scripture here: John the Baptist identifying Jesus as the Lamb (John 1:29) and the angel’s declaration in Revelation (19:9) regarding those “called to the wedding feast of the Lamb.” Our response, “Lord, I am not worthy that you should enter under my roof, but only say the word, and my soul shall be healed,” echoes the words of the Centurion, who asked Jesus to heal his servant (Luke 7:6-7, Matthew 8:5-13). As we are presented with the very Body and Blood of Christ, we are called to the same, deep level of faith as the Centurion.
(By the way, do visit here, click on the word "here" in the lower right hand of the page, and download the new responses to the Mass.)