Double Action Blaster Guys by NovaSquirrel is a single player action game but also allows two simultaneous players. DABG for the Nintendo Entertainment System / Famicom is a sequel to “Forehead Block Guy“.

Since the first revision there’s been several bugfixes and changes:

  • “Extra stuff” menu on the title screen was removed and the level editor and credits were  just moved to the main menu instead
  • If the pre-level screen with the objective is skipped with Start, the game no longer starts the level with the game paused and will wait for you to let go of Start
  • Credits screen now has website URLs on it
  • All unofficial/illegal opcodes are replaced with official ones for better compatibility with emulators that don’t support them
  • Fixed a bug where testing a level in the level editor after beating the game would just bring you back to the title
  • Fixed a bug where enemies can’t climb over blocks from the right

http://forums.nesdev.com/viewtopic.php?f=22&t=10325