With the order in the video:
" Ίστατε έμπροσθεν Βασιλείου, Αυτοκράτορος και Δεσπότου των Ρωμαίων, μάστιγος των εχθρών εμών. Ιδού Ρωμανία" = You stand before Basil, Emperor (Autocrat) and Despot of the Romans, scourge of our foes. Behold Rhomania*
"Κονιορτοποιήσω τας πόλεις σου και νεύσω τους εμού συγγραφέας εξηγείσθε το κράτος σου διά το μέλλον" = I shall crush your cities and signal to my writers so that they describe your nation for the future.
"Αξιοίς τίποτα λιγότερο από του πολέμου, αλλά εν τω αύθονω ελέη μου, συντόμως νικήσω πάρα πολύ" = You deserve nothing less than war, but in my abundant mercy, I shall win very swiftly.
"Τα αριστεία σου, αι μεγάλαι νίκαι σου, προέρχονται από του Θεού. Φροντίσης ως ευχαριστής Αυτώ" = Your displays of excellence, your great victories, they come from God. You should make sure to thank Him.
"Σπανίζεις ενότητος, τιμής, ευσεβείας, παντών ως απεργάζονται τον άρχονταν δίκαιον. Ίσως πρέπει με μιμείσαι" = Unity, honour, piety - everything that makes a just ruler - are hard to come by for you. Perhaps you should mimic me (follow me by example).
"Εύνοιαν αφήρη γε μοι ο Θεός, ως χρεί την Ρωμανίαν συμπίπτειν.Οίμοι, οίαν την συμφοράν" = God has withdrawn his favour from me indeed, as He decrees Rhomania to fall. Oimoi**, what a calamity
*Rhomania (Ρωμανία) is the unofficial name for the Byzantine/eastern Roman empire that its inhabitants used throughout its existence (and for centuries thereafter). It is more aptly translated to "land of the Romans" in Greek and also serves as the root for the modern name of Romania (known in the middle ages in old Romanian as "Teara Romaneasca").
**Oimoi (οίμοι) is an ancient Greek exclamation of grief or despair.
The language as expected is ancient Greek with a modern accent, but it seems more like a mix between Attic and Koine.