So many new things about the map, it would be silly to try to list them all. Here are a few:
East and West sides of the map now look very different
New regen / armor system in place. Each tower race (and specific towers) now have strengths and weaknesses.
Bosses are now typed (except first boss) Lvl 20 boss is Massive / Organic, Lvl 30 boss is Flying / Armored / Lvl 40 boss is Psionic and Robotic.
New "Primary Command" structure with several upgrades and team vs team abilities
3 New T5 towers, one for each race.
You may now build whenever there aren't enemies near your towers.
Wave x9 switched from "no weakness" to a unique wave for each level.
All t5 Towers are now 2x2 placement
You now receive a bonus when the other team is nuked based on the cost of the tower targeted. This bonus is negated if the other team uses invulnerability before the nuke hits (and its a T5 tower)
So many new things about the map, it would be silly to try to list them all. Here are a few:
To get more info or post discussion, got to : http://www.sc2mapster.com/maps/retribution-td/
I'll be putting together an intro video this week.