Once the title screen is finished loading (the Start Normal text is displayed), press Select, Select, A, B, Select, Select, X, Y, Select, Select, L, R, Up. This sets $01 in 7E13B5, and turns the title screen red. Gameplay will now be displayed with alternating-frame stereoscopic 3D, where the output flickers between images for the left and right eyes.
During gameplay, pressing Select toggles $04 in 7E13B7. This disables/enables the 3D effect.
It's very likely that HAL Laboratory intended the game to be used with 3D glasses, a la Rad Racer, but no shutter glasses were ever released for the SNES, so this feature went unused. However, the game does use the I/O pin on both controller ports to signal alternating frames in a way that is compatible with the original Famicom 3D glasses, so it is possible for this effect to work as intended by wiring the appropriate pins from the DB15 connector on the 3D glasses to the appropriate pins (I/O, +5V and GND) on one of the SNES controller ports.
In addition, a modern 3D display which supports alternating-frame 3D should be capable of displaying the game as was planned back in 1991.
A single sprite of Lolo from the Adventures of Lolo series is present among the ship upgrade graphics.
Part of the Halken logo is present among the ending demo graphics. It was used in the opening and ending sequence of the Japanese and European versions of the game, but HAL America replaced it with their own logo for the American version.
The new HAL logo overwrote part of the old Halken one, so only half of it remains in the American ROM.
Bio Plant Background Tiles
A strange organic mass and a similar-looking tile with a grate covering it. Judging from its name and these tiles, the Bio Plant was probably supposed to have a more "organic" theme, but was changed in favor of the flashing lights.
There is also a darkened-out tile of just the midsection of the bio mass. This probably indicates that it was meant to light up, just like the flashing lights that actually were used for this stage.
Weird Font & Dummied Option Menu
Hidden in the background tiles for the microchip background seen in the ending sequence are tiles for the game's title in an unused font, the Japanese copyright information, and what appears to be text for an Option menu that seems to have been removed from the game. It is unknown exactly what "SAR" and "ECD" stood for. It is possible that "SAR" may have been "START" with the "T" being reused from "OPTION", and "ECD" may have been "ENTER CODE", also by reusing letters.
Although the font is unused in the English versions, it is used for the Japanese version's title screen.
The song that plays during the opening demo that shows the HAL (or Halken) company logo is actually a bit longer than what gets played for the few seconds the logo is displayed. The entire song can be heard in the Sound Test.
Hold L + R and press Start on the title screen to bring up a Sound Test. You can test any of the game's 13 songs and 21 sound effects.
Area Clear Extra Life
After defeating a boss, you are given a few seconds before the stage ends. If you use this time to modify your ship's speed, and the value is exactly 333 when the Area Clear message appears, you will get an extra life.
The Japanese title screen is more "industrial"-looking with its logo, and misspells "Laboratory".
In the Japanese version, the Old Capital is Area 1 and the Material Factory is Area 3. In the American and PAL versions, the Material Factory is Area 1 and the Old Capital is Area 3. Some of the stage enemies got moved around as a result of this change, but not the bosses.