The game spans seven levels from Earth to the aliens' home planet, each following a linear path that culminate with a boss.

Though billed as a 3D game, Shin'en used realtime encoding and resizing to manipulate the size of 2D sprites instead of creating a true 3D environment.

The graphics and sound were generally praised; a year after its release, critics at Extended Play still considered it the best-looking game on the platform.

Some are easy to destroy; others, including the fire creatures found on the Iridion home world, are indestructible and must be avoided.

[3]: 27 Manfred Linzner began developing a shoot-em-up video game in 1996 on his Amiga computer, but abandoned the project after producing a single level and some related music.

Linzner later co-founded Shin'en Multimedia in 1999, and Iridion began development as a shooter for the Game Boy Color.

[7] Although advertised as a 3D game, Iridion 3D uses solely 2D graphics for texture scrolling and sprites which depict explosions and enemies.

The developers created the illusion of 3D by looping background textures—a graphically intensive technique for the Game Boy Advance.

[11] GameSpot's Ben Stahl noted the excellent graphics and high frame rate, ending with, "At this point, Iridion 3D looks like it could be a great game for fans of the genre.

[31][8][32] A year after its release, Extended Play's Miguel Concepcion argued that Iridion remained the best-looking game for the system.

[25] Miguel Lopez of GameSpot lauded the graphics, writing that "while it's ultimately all smoke and mirrors, Iridion's world is richly detailed, has remarkable depth, and is unbelievably fluid.

It's often hard to tell if the game's backgrounds are composed of streaming full motion video or just some really fancy math-powered 2D bitmaps.

"[20] Less positively, Aaron Curtiss of the Los Angeles Times wrote that the faux-3D visuals of Iridion were a letdown compared to true 3D games like F-Zero: Maximum Velocity.

[22][25] GameSpy's Andrew S. Bub and Game Informer's Jay Fitzloff criticized the craft placement, as the player's view was often obscured by their own ship.

[8][19] Edge and others observed that Iridion's replay value was low,[20][21][16] while Curtiss wrote that the changing environments helped keep the game interesting.

[22] Cindi Lash of the Post-Gazette praised the soundtrack as demonstrating the promise of the Game Boy's hardware to leave "tinny carousel-like tunes" in the past.