The Sistine Chapel is, of course, a chapel. Larger than many parish churches, but tiny compared to St. Peter’s. It is named after Pope Sixtus VI, in whose honor it was built in the 15th century. Its function has always been closely related to Papal business – gatherings of the Papal Chapel or meetings of the conclave to elect a new pope.
I’ve been there twice – in one day! It was a study in contrasts. Our first tour was private, before the Vatican Museums opened – the room was hushed, with a few other small groups. Our guide said one of the best things about giving before or after-hours tours was that she could actually see the floor of the Chapel, which holds much interest on its own. The second was with the rest of every one of the tourists in Rome that day, after our little private tour had ended and we went back through the rest of the Museum on our own. I wrote about it here.
What I want to point out in relation to today’s Mass is something Liz showed us. There is nothing accidental about the interior decoration of the chapel, including Michelangelo’s Last Judgment  on the wall behind the altar. It is purposefully designed to provide a “space” for a large altar cross. The cross is set up to be directly below the figure of the Risen Christ – and these are the images which we – and the celebrant – face during Mass. To set up another altar in front of that and have the focus shift away does, indeed, violate the original intention of the space.
(She also made the point that the prominent and vivid depiction of the Last Judgment was intended to be a reminder to the clerics gathered in the chapel to make their decisions and cast their votes – there are consequences – eternal ones – to what happens here)
(Random notes from today…apparently the Pope misplaced his ring at some point before the final procession…he mispronounced one of the babies’ names and was gently corrected by the father…)
(It’s also worth noting that – apparently – the Mass was in Italian and Eucharistic Prayer II was used (correct me if I’m wrong), showing, I think that this posture has a place in the way most Catholics experience the Mass around the world.)
From the Pope’s homily, translated by Teresa Benedetta at PRF:

And this, dear brothers and sisters, is the mystery of Baptism. God wants to save us, having gone himself to that abyss of death, so that every man – even he who has fallen so low as to lose sight of heaven altogether – may find the hand of God to grasp ,and come out of the darkness to see the light for which he was made.
We all feel and perceive interiorly that our existence is a desire for life that calls for fullness and for salvation. This fullness of life is given to us through Baptism.
We just heard the narration of Jesus’s Baptism in the Jordan. It was a Baptism different from that which these babies are about to receive but not without a profound relationship with it.
Basically, all the mystery of Christ in the world could be summarized in the word ‘baptism’, which in Greek means ‘immersion’. The Son of God, who from eternity shares the fullness of life with the Father and the Holy Spirit, was ‘immersed’ in our reality as sinners to make us participants in his own life. He was incarnated, born like us, grew up like us to be an adult, and then manifested his mission starting with his ‘baptism of conversion’ by John the Baptist.
His first public act, as we just heard, was to go down to the Jordan, mixing with penitent sinners, to receive that baptism. John naturally did not want to, but Jesus insisted, because it was the will of the Father (cfr Mt 3,13-15).
Why then did the Father want this? Why did he send his only Son to the world like a Lamb to take on himself the sins of the world (cfr Jn 1,29)? The evangelist narrates that when Jesus emerges from the water, the Holy Spirit descended on him in the form of a dove, while the voice of the Father in heaven proclaimed him ‘my beloved son’ (Mt 3,17).
From that moment, therefore, Jesus was revealed as he who came to baptize mankind in the Holy Spirit; he came to bring men life in abundance (cfr Jn 10,10), eternal life, which resurrects the human being and heals him entirely, body and spirit, restoring him to the original plan for which he was created.
The purpose of Christ’s existence on earth was precisely to give mankind the life of God, his Spirit of love, so that every man may draw from this inexhaustible spring of salvation.
That is why St. Paul would write to the Romans that we are baptized in the death of Christ to have life in his Resurrection (cfr Rm 6,3-4). That is why Christian parents like you bring their children as soon as they can to the baptismal font, knowing that the life which they have transmitted to them calls for the fullness and salvation that only God can give. In this way, parents become co-workers with God in transmitting to their children not just physical life but also spiritual life.
Dear parents, together with you, I thank the Lord for the gift of these children and I call on his assistance so he may help you to educate them and place them within the spiritual Body of the church.
As you offer them what they need for growth and for health, you, with the aid of the godparents, are also committed to develop in them faith, hope and charity, the theological virtues which belong to the new life given them by the sacrament of Baptism.
Assure them of these virtues by your presence, your affection. Assure it, first of all and above all ,with prayer, presenting them to God daily, entrusting them to him at every stage of their life.
In order to grow healthy and strong, these babies will, of course, need material care and much attention, but what they will need most, indispensably, is to know, love and serve God faithfully in order to have eternal life. Dear parents, be for them the first witnesses to authentic faith in God.
The sacrament of Baptism has an eloquent ritual which expresses precisely this transmission of the faith. It is the offering, for each of the baptized, of a candle lit from the Easter candle. It is the light of the resurrected Christ which you are committed to transmit to your children.
Thus, from generation to generation, we Christians pass on the light of Christ so that when he returns, he may find us with this flame burning in our hands.
In the course of the ritual, I will tell you: “To you, parents and godparents, is entrusted this Paschal sign, a flame that you must feed”. Feed it always, dear brothers and sisters. Feed the flame of faith by listening to the Word of God and meditating on it, and by assiduous communion with Jesus in the Eucharist.

For more commentary, you’ll want to go to The New Liturgical Movement and Fr. Z. In Rome, Zadok is providing some commentary on press coverage and such. So far, the press coverage has given us ample opportunity to contemplate the many divers meanings of the phrase,  “break from tradition”
More photos at Catholic Press Photo. And the website of the L’Osservatore Romano photography division. If you have three hours and the patience to navigate it.