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Syvalion is an interesting little action game designed by Fukio Mitsuji of Bubble Bobble fame. Control a dragon-shaped spaceship with a trackball through five procedurally-generated chapters. The story, obstacle placement, bosses, and music are all randomized throughout the game. The random nature of the game combined with the size of the player's ship and narrow passageways makes getting through each stage unscathed a bit of a crapshoot.
Some games have error handlers for the standard 68000 exception vectors. Here's one now! This spits out the values of the programer counter and registers D0-D7 and A0-A7 before the game crashed.
This game uses a slightly shorter version of the Taito Code:
- Hold the Service Coin button after the Hardware Initialize screen until a "SERVICE SWITCH ERROR" message pops up on the screen.
- Press 1P Start (x3), then press Service Coin.
This Round Select should pop up after starting a new game.
Place the following code in syvalion.xml to replace the game's normal test mode with a different function:
<cheat desc="Change Test Mode Function"> <parameter> <item value="0x0003D490">Map Edit</item> <item value="0x0003DC74">Object Display</item> <item value="0x0003D856">Color RAM Edit</item> <item value="0x0003DB9C">Color Bars</item> <item value="0x0003DEE2">Block Status Edit</item> <item value="0x0003E3EC">Obstacle Edit</item> </parameter> <script state="run"> <action>maincpu.md@00695A=param</action> </script> <script state="off"> <action>maincpu.md@00695A=0x000040A0</action> </script> </cheat>
It's a map editor, naturally. The combination of an invisible cursor with the release game's trackball controls makes it difficult to really do anything in this editor.
- 1P Trackball: Moves cursor.
- 1P / 2P Start: Changes the currently selected tile.
- 1P Button 1: Places the selected tile on the grid.
- 2P Button 1: Toggles between the map editor and a "Free view" mode.
- 1P Coin: Switches the priority of placed tiles (They'll appear either behind or in front of the grid).
- Service: Changes the current tile palette.
- Tilt: Skips ahead by 64 tiles.
Displays the content of the graphics ROM.
- 1P Trackball: Cycles through tiles.
- 1P Start: Changes the width of each row.
- 2P Start: Changes the "mode", or palette.
- Service: Toggles the tile grid.
Color RAM Edit
A palette editor, much like the one in Taito's Recordbreaker.
- 1P / 2P Start: Moves the color cursor.
- 1P Button 1: Changes the current color value (Red / Green / Blue).
- 2P Button 1: Changes the current palette (00 to 1F).
- 1P Coin: Decreases the current color value.
- Service: Increases the current color value.
This simply displays palettes 03 to 07 as color bars. That's all.
Block Status Edit
A tool to view and edit (well, not anymore) the attributes of each 32x32 level block.
- 1P / 2P Start: Changes the current block number.
- 1P Button 1: Changes the value of the currently selected attribute.
- 2P Button 1: Switches between different attributes.
- Service: Changes the current stage palette.
- Tilt: Skips ahead by 64 blocks.
This tool acts as a level block viewer and tests how objects, obstacles, and bosses can fit in each block. Select which chapter to load in this menu.
Unfortunately, this is another instance where the cursor is invisible, so it's a little difficult to actually control. Up to 8 objects can be placed on screen at a time.
- 1P Trackball: Moves cursor.
- 1P Button 1: Places object.
- 2P Button 1: Toggles visible hitboxes.
- 1P / 2P Start: Switches between different objects.
- 1P Coin: Go to previous level block.
- Service: Go to next level block.
- Tilt: Moves the camera down / up by 64 pixels.
A shiny gold version of the old blocky Taito logo is used on the World prototype's title screen. It's still in the final game's graphics ROM, but the standard "new" Taito logo is used instead.