Mendel Palace

Mendel Palace is a game about pushing tiles and knocking bad guys into walls. It also happens to be the first game Game Freak ever made. Perhaps you've heard of them?

Debug Menu
Enter the Game Genie code, then hold B and press Start at the title screen to activate the debug menu. The options are as follows: Moving the cursor up past DEATH/NO DEATH allows you to change the current tileset, character sprite, and character palette.
 * DEATH/NO DEATH: Turns invincibility on or off.
 * NUMBER OF PLAYER: Number of lives to start the game with.
 * SCENE NUMBER: Select a level to play. The first number determines whether the "EXTRA" levels are active (0=no, 1=yes), and can be changed by pressing Select.

Warp to Final Level
Enter the Game Genie code, then hold Left and press Start at the title screen menu to warp to the final castle.

Unknown
Enter the Game Genie code, then hold Right and press Start at the title screen menu. This marks the fortress at the center-right of the map as cleared.

In-Game Debugging Features
Enter the Game Genie codes, then hold B and press A at the title screen menu to enable a few in-game debugging features.

At any time during the game: While the game is paused:
 * Reset: Press Start + Select to reset the game.
 * Frame advance: Press Start to advance one frame. Press Select to unpause.
 * Swap layers + 98 Stars: Hold Down and press Select to swap the playfield layers and set the Star counter to 98.

Crash Dump
In the Japanese version of the game, if a BRK opcode is executed as the result of a program crash, the game will write a number of CPU registers and RAM variables to the screen before going into an infinite loop. The numbers displayed are as follows:
 * Line 1: Stack pointer, accumulator, X register, Y register, processor status register.
 * Lines 2-13: Contents of the stack.
 * Lines 14-15: Scratchpad RAM.

Regional Differences
The title screen was completely changed for the US release, displaying art of the game's enemy characters.