Gurren-Lagann: Lagann Chapter SPoilers

-Nia's relationship with the cast is greatly enhanced. Obviously it features a good amount of few new Simon/Nia scenes that take a "closer look at their feelings", it was pretty obvious they were trying to make their relationship the center of the story, but there is also plenty of interaction with Yoko and, surprisingly, Viral.

-The new proposal sequence is beautiful. Feels a lot more romantic and has pretty incredible animation. The way in which Nia's hair blows in the wind is always so pretty.

-Kittan may have not a lot of new sequences, but he was very well-portrayed in the movie. And he jokes around with Kamina when they appear to help Simon break free from the "Polysynthethic Universe".

-The final action sequence is incredible, astounding and extremely tiring. It's very climatically tiring. Around 20-25 minutes of newly animated Galaxy-sized action with barely any single moment of rest. I recall the only moment of rest being the minutes of everyone being shocked and angsty over Anti-Spiral's word about Nia dying if he is killed... but that was cut short by Sorubinia's incredibly cool, and hot, appearance. Anyone here has seen the final sequence in the movie Mind Game? The one with the characters trying to escape the whale's inside? They're similar: intensityX1000.

-Anti-Spiral Messenger Nia pilots the Cathedral Terra with Genome inside of it. It looks deranged and insane.
-After Nia is defeated, she turns back to normal and gets her own gunmen. It's named Sorubinia and is basically a white Lazengann.
-There are Yoko and Nia nipples.
-Kittan is the only one who dies. The rest of the group lives.
-Chouginga's transformation is remade and looks better.
-After everyone creates the TTGL it is defeated by the Grand Zamboa.
-Nia gets up and takes on the Anti-Spiral by herself.
-And seeing her fight against the AntiSpiral by herself inspires everyone to "create" their own Tengen Toppa ganmen. It's another sweet sequence: "To be able to protect the Spiral Princess", "I'm not a princess anymore, Viral-San", "You'll always be Gurren-Dan's princess!" "Yoko..." "That's right" and everyone gets their own Tengen Toppa. The dialog isn't exactly like that, though.
-The Anti-Spiral gets an upgrade too.
-After they gattai into Chou Tengen Toppa, they have a sequence similarto the one in the TV show in which Tengen Toppa's Giga Drill comes out from Chou Tengen Toppa's Giga Drill, Chou-Ginga's Giga Drill comes out from Tengen Toppa's GIga Drill and so and so until Simon himself gets
to the Anti-Spiral by himself and faces him in hand-to-hand combat.
-The marriage and Nia's death are much better.
-Simon travels the world and plants flowers everywhere in Nia's memory.