Thunder Cross

Thunder Cross is a horizontally scrolling shoot 'em up arcade game released in arcades by Konami in 1988. Thunder Cross used a "layered scrolling" background, a new 2D graphics technique at the time. A sequel, Thunder Cross II was released in 1991.

Both Thunder Cross and Thunder Cross II take place in the same universe as the Gradius series. The planet Haniamu IV is under attack from a relentless, unknown military force known only as Black Impulse. Humanity sends the Blue Thunder M-45 and its earlier make the Red Thunder M-24 to take care of them.

Not to be confused with the Thunder Force shooter series. And definitely not to be confused with the alternative name for the swastika.

Thunder Cross and its sequel provides the following examples:

 * Attack Drone: The Options. They stay at the sides of your ship, although you can control the distance between options (in the Japanese/European version of 1, and in II)
 * Attack Its Weak Point: Most of the bosses have a crystalline core which you must damage in order to defeat them.
 * Battleship Raid: Stage 4 of the first game, and Stage 5 of II.
 * Continuing Is Painful: And how. You lose ALL your powerups when you die! It does reset the Dynamic Difficulty, though.
 * Corridor Cubbyhole Run: Stage 6 of II has your character move through an asteroid field while the boss fires a Wave Motion Gun from offscreen. In order to avoid the laser easily, you have to hide behind the asteroids that block it.
 * Difficulty By Region: The US version of Thunder Cross gave your character Smart Bombs in exchange for the ability to control your options.
 * Dynamic Difficulty: Get enough powerups and the annoying turret enemies will exhibit More Dakka, in a fashion similar to Gradius.
 * Expy: Some of the bosses in the series are similar to those in Gradius.
 * There's also the "wave" of popcorn mooks that drop a Power Up when all of them are destroyed.
 * Gratuitous English: The second game has boss names like "Brookrans, Works", "Laze, Zoguylum", and "Sproutes, Layber".
 * Kill It With Fire: The flame weapon from both games. In 1, it was a continuous medium-range stream of flame, in II, your Options shot out phoenixes that pierced enemies.
 * Humongous Mecha: Most of the bosses that aren't ships.
 * Mini Boss: Each level usually has one in the middle.
 * Mutually Exclusive Powerups: The primary weapons you could use, as well as the "special" weapons (Napalm, Flame, Laser).
 * One Hit Point Wonder: Your character, like most games in the genre.
 * Palette Swap: Player 1 (Blue Thunder) and Player 2 (Red Thunder).
 * Reactor Boss: "Brookrans, Works" from II is the core of a large battleship.
 * Recurring Boss Template: Eggeroid, which appears as the first boss in both games. In the first game, you could attack its weak point directly, in the second, you had to attack its tail first.
 * Reptiles Are Abhorrent: In II, the Black Impulse have two repilian bosses (Ragamuffin the robotic naga and Dinosaur Junior the robot chameleon).
 * Shared Universe: Thunder Cross takes place in the same universe as Gradius.
 * Snake People: Ragamuffin from II is a robotic Naga with a shield, rocket launcher, and a stinger tail.
 * Sphere of Destruction: The Napalm Weapon makes your options shoot out a bomb that explodes into these.
 * Too Awesome to Use: Subverted with the special weapons. Although they do have limited ammo, hit a large area of the screen, and hurt A LOT, you can easily find more ammo once you run out. Furthermore, they replace the primary weapon of your options, and the only way to revert them back was to run out of ammo.
 * Wave Motion Gun: The Laser weapon from both games allows all your four options to fire out one!