At 2:40 We have a possible indication to the Magnums bloom, the enemy was firing at a faster rate of accurate fire than previously before, more like Halo 1 Magnum rate of fire.
At 3:24 We can clearly see that bleedthrough is indeed present.
At 4:17 We can clearly see a DMR going full auto with no bloom. And again at 4:53.
At 4:28 We can clearly see that the Armour lock Frosting issue has been addressed, the moment when the player starts to emerge from Armour lock, he takes damage from a Frag that went off nearby. Also it seems that your energy depletes when you take damage in Armour lock ( Thanks to The Little Moa and Drowsy Demon for all the Armour lock information)
At 1:18 It looks asif Movement acceleration has been heavily tweaked ( Where when you strafe your character starts off slow then builds up to full speed ), so now it looks like you can actually strafe effectively.
It appears movement and jumpheight have been slightly increased, by 5/10% each.
And Sticky grenades appear to do less damage when they freely explode on the ground. Frags look like they bounce abit more too.