The only issue discovered was with the menu. Sometimes when selecting a world and a level, the selection would get stuck. As an example, if level 5 was highlighted, but you wanted to go to level 8, it would be stuck on level 5. If this happenes, you need to back out, and go back into the world menu, and it will fix itself. It only happened 2 or 3 times during the playthrough.
Other than this, the game was flawless.
After beating the main game, the original game (Gunbrick) will be unlocked. Here again, the original game played flawlessly with no issues.
Completed 100%.
The only issue discovered was with the menu. Sometimes when selecting a world and a level, the selection would get stuck. As an example, if level 5 was highlighted, but you wanted to go to level 8, it would be stuck on level 5. If this happenes, you need to back out, and go back into the world menu, and it will fix itself. It only happened 2 or 3 times during the playthrough.
Other than this, the game was flawless.
After beating the main game, the original game (Gunbrick) will be unlocked. Here again, the original game played flawlessly with no issues.