This is the day when Christians remember that the Roman governor didn't want to deal with him, shipped him over to the Roman-installed King Herod Antipas, who fancied himself a Greek, and sent him back to Pilate. The tradition was to release a prisoner to the people, and Pilate offered to free Jesus of Nazareth, or Jesus Barabbas, and the crowd called for Barabbas, a murdering terrorist. (The crowd was apparently Sanhedrin employees, followers, and partisans in some part, the rest being like Judas Iscariot, people who expected that Jesus would, at any moment, call the Army of God from heaven to destroy the Romans and bring about the new world; but he'd possibly failed to do that too often for them.)
This is the day we remember how Jesus was "crowned" in mockery, using a crown woven of thorns. The roman soldiers felt that it was unfitting that a king should be without a crown, and (if the bits of the supposedly preserved crown are authentic) wove thorns from a jujube tree with some reeds into a spikey crown, then jammed it onto his head, beating him around the head and shoulders with a staff.
This is the day we remember that Jesus was scourged. There's a medical account of the scourging and crucifixion behind this link. The salient points: Scourging is done using a weighted whip with sharpened bones and lead balls on the end of braided leather thongs, about the length of a sword; the scourge was slammed into the back and yanked across, causing deep bruises, and tearing the skin open. They did this at least forty times. After the first two blows, the skin and muscle in an area is deeply lacerated and bruised. Ten was considered a crippling sentence, thirty could kill. Jesus was then required to carry the cross-bar to the crucifix that he would die on, from the center of town to the place of execution. This was a typical sentence, but Jesus was too badly weakened by the scourging and fell too many times, so they grabbed someone from the crowd and compelled him to carry the approximately 120 pound cross-beam.
This is the day we remember the crucifixion. The nails were square, probably six inches long, more like railroad spikes. They were driven into the wrist below the thumb and between the two bones so that they wouldn't tear loose from the weight of the body. The cross bar was then hung up on the post, and the sign stating the "crime" was nailed so it showed above the head. They didn't use seats or foot-posts in Jesus' time, they simply nailed through the arch of the foot at the top of the ankle, then the other foot, then into the post. This was intended to be a painful torturous death. The position is one where it's hard to exhale. The only way to do so is to push up with the feet (impaled on the spike at the bottom) and pull on the wrists (partly shattered and in excruciating agony) for just long enough to exhale. Jesus, like anyone who was crucified, was expected to suffocate. He was already nearly dead from the beating. His death was faster than expected; it only took a few hours instead of more than a day.
Since it was approaching evening, and thus the beginning of the Sabbath, the Sanhedrin representatives asked the Romans to finish him off; they would have broken his legs, which forces suffocation in about five minutes. But he was already dead; in order to make sure of that, one of the soldiers stabbed him with a spear or sword into the heart. Blood and pericardial fluid gushed out the opening. That blow itself would have been fatal.
They normally gave the bodies of the crucified dead to their relatives, and Mary the mother of Jesus was there, and Joseph of Erimathea (a follower of Jesus' and a wealthy man) had the body taken to his own tomb that he had recently finished, and the women prepared it for burial. Soldiers were stationed at the tomb to prevent the body being stolen, and a very large rock was rolled across the doorway.
This is the day we remember that Jesus died a horrible, agonizing death by slow torture.
If that isn't enough to satisfy our view of God's requirement that transgression is paid for, then there is no satisfaction for it.