Super Robot Taisen Original Generation - Unlock Shishio Blade

Unlock Graviton Launcher:
Make sure your opposite main character Ryusei or Kyosuke has at least at least 55 kills by stage 32.

Unlock Hero Symbol:
Daitetsu Ryusei Route or Lefina Kyosuke Route must be at least level 35 by stage 35.

Unlock Soul of Metal:
Daitetsu Kyosuke Route or Lefina Ryusei Route must be at least level 38 by level 38.

Unlock Keep the ability to combine into SRX:
Take the Ryusei Route.

Unlock Valcion Kai:
On stage 28, reduce the HP of the Valcion Kai below 10 without destroying it.

Unlock R-GUN:
Destroy it on stage 30.

Unlock Lion-F:
Take the Ryusei Path.

Unlock Guarlion:
Destroy it with either Task or Rai on stage 24.

Unlock Huckebein 008L:
Have Ingram be at level 32 before stage 30 Ryusei Route or Villeta at level 23 by stage 19 on the Kyosuke route.

Unlock Grungust:
Destroy the R-GUN on stage 30 on Kyosuke's path without getting the Huckebein 008L.

Unlock Gespenst-S:
Destroy the R-GUN on stage 30 on Ryusei's path without getting the Huckebein 008L.

Unlock Gespenst-R:
On the Kyosuke Route, make sure Guilliam is at least level 23 by stage 19.

Unlock Kai:
Take the Kyosuke Route.