Satake originally began development of an arcade game in the late 1980s based around themes of steampunk aviation, inspired by anime such as Laputa: Castle in the Sky and Future Boy Conan.
[5] In this "Age of Steel", mammoth, floating, steam-powered battleships cruise the skies and gigantic armored locomotives carry cannons the size of railway cars.
A military coup has occurred in the world's largest city, Damd ("Dama" in Asian markets) and power-hungry dictator, industrialist and robber baron General Styron ("Sauron" in Asian versions) rules by brute force and military might, his Goliath-like defenses carrying armor-piercing missiles and lethal aerial mines.
This is the Republic of Silverhead, placed far from the reach of the Steel Empire, centered in Antarctica, and where some of the greatest minds in the world have fled from Styron's tyranny.
If the wider world were to also harness the power of lightning and the atom, it could pose a threat to Styron's coal and steam-based status quo, and so the dictator wants all "abominations of nature" ended.
The game begins with the Motorhead Empire attacking the mining city of Rahl, an ally of Silverhead in southern Patagonia,[6] and the player is tasked with retaking it.
Further missions will take the player into the vast subterranean (and partially submerged) caverns of Liedengel, where the Motorhead are gathering a surprise attack force against Silverhead; Sky District Zektor; and the foremost defenses of the Steel Empire—the heavily fortified Gardandi Islands, which lay in front of Damd, the Motorheads' capital city.
[8] If the player is victorious, Styron's ship is shown crashing to the moon, the credits play, and "The End" shows over a bleak lunar surface beneath the glowing Earth.
Small blasts of explosive directed energy are used by the aircraft fighters of Silverhead as a form of standard, unlimited ammunition; although this is not greatly effective against the majority of the heavily armored forces of the Steel Empire and its allies, and is virtually ineffective against the bosses and mini-bosses.
These power-ups include: Steel Empire features a kind of leveling-up system; every three powerups increase the player's firepower strength by one level, up to a maximum of 20.
The bosses and mini-bosses include larger and more heavily armored rare enemies such as flying ironclads, and gigantic, steampunk-inspired mechanical golems.
As well as the standard energy-based ammunition of Silverhead aircraft to fire ahead and to the rear, the Striker will launch secondary blasts diagonally down towards ground-based targets, an advantage not shared with the other craft available.
Compared to the Striker, the Z-01 is larger, and therefore a bigger target, and is slower; yet is significantly tougher and more durable, being able to take more punishment from enemy firepower.
The Z-01s specialty is aerial mines launched upward, which fall further away in a wide crest motion; this makes it more suited to skyward assaults than the Striker, and qualifies it as more of an interceptor aircraft.
Steel Empire saw successful sales in both markets, and acquired cult status in Japan, and to a lesser degree also in the Western world.
[10] Sega Power magazine gave the game an overall score of 54 out of 100 stating "The graphics are different, the aliens are different, the attack patterns are different but the gameplay’s exactly the same as other Mega Drive shoot-em-ups.
Satake envisions it as a "grittier" game than the original, which he would call Burning Steel, explaining: "To make a proper sequel I'd probably need more development funds than we had for the GBA version.
I have an idea for a sequel titled "Koutetsu Moyu" [something like Burning Steel, though its a bit of a play on words, since the 'yu' can also be read in this compound as "oil" or "fuel".]
"[9]In August 2013, Starfish announced its intention to release another remake of Steel Empire, this time for the Nintendo 3DS handheld system.