Tetris Attack (Game Boy)

A low-effort port of the SNES version with slower gameplay, remixed music, less color, and a suspicious dearth of upside-down triangle panels.

Hidden Super Game Boy Borders
There are six custom borders, accessible when you play the game on a Super Game Boy, hidden away and unlockable via button codes. The codes to access them are entered at the title screen, when selecting "1P" to play the game. They are:


 * Down + A: Yoshi stage border
 * Left + A: Gargantua Blargg stage border
 * Up + A: Poochy stage border
 * Down + Start: Froggy stage border
 * Left + Start: Lakitu stage border
 * Up + Start: Raphael Raven stage border

Returning to the title screen at any time allows you to choose another border. Returning to the title screen and pressing only Start will make the border the default star border again, while pressing A button keeps the current border.

Unused Super Game Boy Functions
There is quite a bit of evidence that would suggest that additional palette settings were planned, possibly fitting each of the hidden borders?

MASK_EN
Used to mask the game screen to prevent garbage from showing from VRAM transfers (borders and other information). Setting bit to  unfreezes the game screen, when set to  the image is frozen with the current picture, when set to  the screen is black and when set to  the screen is set to the defined palette 00 setting.

Located at are two unused MASK_EN commands. Since palette setting 00 is undefined, the command is ignored displaying the game.

PAL_SET
Used to set the indirect system custom enhanced Super Game Boy palette setting or to copy pre-defined logical palette data from Super Game Boy system colour palette designated by the loaded PAL_TRN data to an actual Super Game Boy palette. PAL_TRN palette information should be set before initialising PAL_SET.

Starting at is an entire table for unused PAL_SET entrees. Only the first entree located at is used and is loaded on all borders with bit  palette attributes set to.

PAL_PRI 00
While listed as an unknown Super Game Boy packet, when bit is set to , palettes do not switch back to default when directed to by the game, and since there is only one very bland palette setting for Tetris Attack, this is unnecessary and leftover from a probable early idea to include additional palettes and to have them switch back to the default game's palette as seen in Kirby's Dream Land 2, Donkey Kong (Game Boy), Donkey Kong Land and others. Adding the command may have been a very early design decision.

PAL_PRI 01
Game Genie code will set the PAL_PRI bit to. There is also code to load the command, but it is never called.

Removed Packet Calls
Empty space for dummied packet calls, likely belonging to the unused PAL_SET commands is found at. There is code to load this command though it is never called.