Chapter 2 : Training, Mach drills

I didn't understand the first half of the story at all. I only know Ikki and Alice is going back to the base? that have been destroyed on chapter 1. 

The background of this chapter is from Kotetsushin Jeeg series. The other half of the stroy is about Jeeg training, where tsubaki from Jeeg series is explaining about the training but Jeeg's main character, Kenji,fell asleep. Tsubaki is mad at Kenji of course. And then another Jeeg character, Koji and Sayaka from Mazinga Z along Boss and his two sidekick Nuke and Mucha also from Mazinga Z decided to teach Kenji a lesson. Before the training begins, Kenji mecha need to a part from tsubaki's Big Shooter to form Jeeg, this process is called "Build Up". But when the part is shot from Tsubaki's Big Shooter, Koji with his Mazinga Z launches rocket punch toward Kenji, The build up process is failed. The other units are also attacking Kenji. Tsubaki who is mad at Kenji also attacking Kenji. After a while Kenji succeed to "Build Up" Jeeg.

Now for the Mach Drill training, Mach Drill is a part also from Tsubaki's Big Shooter. But Tsubaki is still mad at Kenji and send Mach Drill with an incredible speed, making Jeeg fails to catch the Mach Drill. Before the real training start, they are attacked by enemies, now there's no time for training, they should take care of the enemy first.

We have 6 new units :
1. Jeeg from Jeeg series with Kenji as its pilot
2. Big Shooter from Jeeg series with a guy that i don't know his name as its pilot and tsubaki as its co-pilot
3. Build Angel from Jeeg series with a girl that i don't know her name as its pilot
4. Mazinga Z from Mazinga Z series with Koji as its pilot
5. Afurodai A from Mazinga Z series with Sayaka as its pilot
6. BossBorot from Mazinga Z series with Boss as its pilot and his two sidekick as co-pilot.

The enemies' boss has an unpenetratable armor in this stage. No matter how strong your attack is the damage will be 0.

At turn 3 we get 4 reinforcement consist of Rushbird, Painkiller, Hind Kind and a new unit called Deceive from Linebarrel with Sizuna as its pilot and Izuna as its co-pilot. Like Hind Kind's pilot and kouichi, Some of Izuna attack's animation have Izuna on her berserk/crazy mode.

After all enemies are defeated, the enemies' boss is the only enemy left but it has a unpenetrable armor. And then Jeeg used Mach Drill from Big Shooter to destroy the enemy's armor.