Koen had a lot of fun in this: lots of unnamed mechs, plus some weird images in the giant screens. Are those Gobots? And what about the miscolored Grendizer in the crowd?
Panel 2.
On the left, a hint of the mysteryous storyteller, Jhiaxus. On the right, Guardian Prime.
The name "Guardian Prime" comes from the Dreamwave continuity. In that continuity, he was supposed to be the Prime that came before Sentinel Prime.
Panel 4.
The Pagoda Supreme is another location that has become a trademark of our saga.
Panel 5.
What is the Abyss Resurgence? Who dwells under the Sea Of Rust?
Energy-based weapons. Guardian is using an Energo-sword, in Grimlock style. Nova is using a spiked ball, reminescing of Megatron's "Morning Star" (see G1 cartoon episode "More Than Meets The Eye").
Panel 8.
Nova Prime's plan is revealed, as per Spotlight: Optimus Prime and Revelation.
The contrast between the theoretical nobility of a Prime and the G2 feel of the fanatical supremacist Nova Prime was first raised/explored by Ibai Canales and Peter Istyle.