I was listening to the live stream of the arraginment. Here are some details (I may have gotten some things wrong - it went by quick). Sounds very, very bad for Hernandez. Note that this is the prosecution's side only, the defense doesn't get a chance to ask questions or challenge any claims
They have video of Hernandez getting into the altima with a gun saying "you can't trust anyone anymore"
They have gps cell tower data from Hernandez and Lloyd's cell phones showing Hernandez driving to Lloyd's house then driving to an industrial complex near Hernandez's house. There's video footage of the driving up to the gravel lot where Lloyd was shot and then driving away a few minutes later. During those minutes multiple witnesses heard gunshots. There's video footage of Hernandez arriving back at his house and footage of him and his associates leaving the car for the house with guns.
They have texts from Lloyd saying he was in a car with "nfl" on the drive to the industrial park
The rental agency found a shell casing in the car. They also found chewed gum that Hernandez bought earlier in the night.
They're saying from the injuries that they shot Lloyd as he was trying to get away, then shot him twice more while standing above him, and that Lloyd tried to shield himself from the killing shot with his arm
They do not have the murder weapon.