Sky Adventure is pretty much Sky Soldiers reimagined as a...different shoot 'em up.
Some debug features are enabled if the game is able to write to address 0x00074 in the main CPU. This isn't possible to do in the retail game, since that space is used by the exception vector table, but was probably possible in development versions. Place this cheat in MAME's skyadvnt.xml cheat file to bypass that check:
<cheat desc="Enable Debug Functions"> <script state="run"> <action>maincpu.mw@0B448=6600</action> <action>maincpu.mw@14E76=6600</action> <action>maincpu.mw@14EFA=6600</action> <action>maincpu.mw@14F00=0007</action> </script> <script state="off"> <action>maincpu.mw@0B448=6700</action> <action>maincpu.mw@14E76=6700</action> <action>maincpu.mw@14EFA=6700</action> <action>maincpu.mw@14F00=0006</action> </script> </cheat>
- Set the "Unused" dip switch (A3) on to make both players invincible.
- Set the Difficulty dip switch (B5) to Hard to display the stage scroll position in the upper-left of the screen. This increases by 1 every 32 frames. At 0071 the mid-boss fight starts, and at 00F1 the boss fight starts.
- Hold 2P Start to make the stage scroll 32× faster.
- NOTE: This is supposed to be toggled by 2P Button 3, but no such button exists on the retail unit. The MAME cheat changes it to 2P Start.
Sound Board No.62FC01 Music Macro Lungeag & Effect Macro Lungeag & Adpcm Voice Out Control Program ALPHA DENSHI CO., LTD. By Satoshi.Hagitani
Most of the HUD graphics bank is left over from Sky Soldiers, including these still-unused flags.