Thunder Force III

Thunder Force III is a scrolling shooter game developed by Technosoft. It is the third chapter in the Thunder Force series. It was released in 1990 in Japan, Europe and the United States for the Mega Drive/Genesis game console. During the same year, it was retooled into an arcade game named Thunder Force AC. In 1991, Thunder Force AC was ported to the Super NES/Super Famicom, renamed Thunder Spirits.

Story
The setting of Thunder Force III takes place about 100 years after Thunder Force and directly after Thunder Force II.

Apparently, despite their successes, the Galaxy Federation has not been faring well in their battle against the ORN Empire. ORN has installed cloaking devices on five major planets in their space territory that conceal their main base, making it difficult for the Galaxy Federation to locate and attack their headquarters. In addition, ORN has built a remote defense system to protect itself named Cerberus, which is especially efficient at neutralizing large ships and fleets. Knowing this, the Galaxy Federation creates the FIRE LEO-03 Styx; a craft small enough to avoid detection by Cerberus, yet equipped with the firepower of a large starfighter. The Galaxy Federation deploys Styx (which is controlled by the player) on a mission to destroy the five cloaking devices, infiltrate the Empire's headquarters, and destroy its emperor, the bio-computer "Cha Os".

Gameplay
For Thunder Force III, the free-directional, overhead stage format featured in the previous two games is removed and replaced entirely by the horizontally aligned stage format. The horizontal format becomes the new standard for the following games.

The player is allowed to choose which of the initial five planets (Hydra, Gorgon, Seiren, Haides, and Ellis), to start on. After the first five stages are completed, the game continues for three more stages into ORN headquarters.

The weapon system from Thunder Force II returns in this game, with some modifications. Some weapons from Thunder Force II are reused or modified slightly (the enhanceable Twin shot and Back shot remain the defaults), while others are completely new and exclusive to the game.

This time, when the player's ship is destroyed, only the weapon that was currently in use is lost (unless it is a default weapon and assuming the game is operating at the default difficulty settings). On any higher difficulty modes than the default one, all weapons are lost when the ship gets destroyed. CLAWs also make their return and have the same behavior and functions, except now when the player collects the CLAW item, the ship automatically receives its maximum two CLAWs (again, CLAWs are lost upon ship destruction in every difficulty modes). Also, when using most weapons, the CLAWs will mimic the ship and fire the same weapon (similar to the Options in Gradius games). The final new addition is that the player's ship now has a speed setting, which can be increased or decreased across four levels at the press of a button.

By pressing "A" or "B" or "C" and "Start" buttons at the same time on the title screen, the player gets access to Option screen, where the player can change difficulty settings, listen to soundtracks, set the ship's default speed, etc.

Reception
In 1990, The Games Machine praised the game as "the best shoot 'em up on the Mega Drive." In 1992, MegaTech magazine praised the use of parallax, a well as the sound and gameplay. Mega placed the game at #17 in their list of Top Mega Drive Games of All Time.

Differences between versions
The main difference between Thunder Force III and its variations, AC and Spirits, is that the "Haides" and "Ellis" stages in Thunder Force III are not found in the variations and are replaced with entirely new stages. The variations also removed Thunder Force III's gameplay option to choose the starting stage and always start on the "Hydra" stage. Also, some of the instruments and music tracks are noticeably different.