Alltynex Second

The first entry in Siter Skain's "The Tale of Alltynex" trilogy, it takes place before RefleX and Kamui, despite being released after either one of them. It is a remake of a game for the FM Towns called Alltynex, developed by a man named Satoshi Yoshida (who later went on to form Siter Skain), with massively upgraded graphics and some game design changes (the original had powerups, Second does not). The fighter the player flies has several weapons: a vulcan spreadshot and a Ray Storm-style homing laser, and can transform into a slower mech that has two bullet-cancelling swords and a Wave Motion Gun. Mastering switching between the forms and knowing which weapon to use when is essential.

The story is largely unknown due to being in Japanese (if anyone happens to know it, please add to this), but what is known is that mankind's defensive supercomputer, ALLTYNEX, one day goes rogue and uses its control over military hardware to start waging war on humanity. In the face of its onslaught, humanity is driven off of Earth and to the very edge of the solar system. In desperation, several "superfighters" are dispatched to destroy ALLTYNEX before it destroys everyone else. The rest of the plot is untranslated, but contains several Call Forwards and references to both RefleX and Kamui, and hints that ALLTYNEX may not have gone rogue on its own...

Tropes used in Alltynex Second include:

A.I. Is a Crapshoot: An omnipresent trope in this series. ALLTYNEX itself being the primary example.
Apocalypse How: Class 1- 85% of the human race is wiped out in 72 hours by ALLTYNEX's first assault.
Battleship Raid: The Zoldyzant Base
BFS: They are twice as big as your ship and you dual wield them.
Boss Subtitles: Most of them are simply "Guardian Soldier", but ALLTYNEX gets "Mother Brain" and Satariel gets "Visitor from Qliphoth".
Bullet Hell
Call Forward: The final line of defense before ALLTYNEX is a ZODIAC: the shell of Ophiuchus, to be exact. A remix of "Raiwat Virgo" also plays during the battle. In addition, the eight Kamui fighters are mentioned in the credits, as well as the name of the scientist who invents the Phoenix Mk II.
Cores and Turrets Boss: ALLTYNEX itself.
Degraded Boss: ZODIAC Ophiuchus is nowhere near as powerful as the ZODIAC's seen in RefleX, but that makes sense, as Ophiuchus is lacking its core. Said core is dug up in RefleX and used to build the Phoenix MkII.
Difficult but Awesome: The advanced ship.
Fragile Speedster: The fighter mode. It is fast enough to avoid most enemy fire, and is capable of filling the screen with More Dakka and homing lasers, but its weapons aren't all that strong.
Gratuitous English: The boss warnings. "An enemy plane of the ALLTYNEX operation system deployment model is coming close. I shift into a phase with the second battle mode. I fight back immediately and please overthrow it. A goddess of the victory smile at you."
Harder Than Hard: The Suicide Bullet difficulity.
Kill Sat: ALLTYNEX whips one out near the end of Stage 4. You, unfortunately, are not in orbit at the time, and so just have to dodge around the giant beam of death.
Lightning Bruiser: Alacran, and being a Call Forward to Scorpio it has to be.
Macross Missile Massacre: Sometimes launched against you, mainly because the swords are not fast enough to block large numbers of missiles.
- The advanced ship can launch these as well.
The Man Behind the Man: Satariel, which emerges from the core of ALLTYNEX after you destroy it.
Meaningful Name: Satariel is the name of one of the leaders of the renegade Grigori who precipitated the Nephilim disaster in the Book of Enoch.
Mighty Glacier: The mecha mode. It is very slow, but both its swords and giant beam weapon can cancel bullets and do huge amounts of damage.
Nintendo Hard
Ominous Pipe Organ: Just like the original so does the remix of "Raiwat Virgo" have these.
One-Hit-Point Wonder: Not quite. The ship's Defense Shield can absorb one and only one hit, and it cannot be restored unless the player dies.
Outside Context Villain: Satariel.
Roboteching: All over the place. This time the player has roboteching homing lasers of their own.
Shout-Out: The 3rd form of Adonis is looking strangely familiar.
- The player ship's beam weapon is apparently called the "Buster Rifle".
Tank Goodness: Ajattara.
Transforming Mecha: The player ship. Most bosses will also go through several transformations during battles.
Video Game 3D Leap: The first game in the series to us 3D graphics.
"Wake-Up Call" Boss: Ajattara.
Wave Motion Gun: The mech has one. Lots of bosses have them as well.