So, I recently found that the rom of the game found in many websites today is not the actual game. Long story short: The rom is a "romhack" that for some reason, the author removed the intro, and very recently, two guys decided to get an original copy of the game and dump it into a computer file, and the original copy of the game actually had an intro, showing "SEGA", "TecToy" and some basic copyrights at the start of the game.

I played around with the game for some minutes and didn't find anything other than that different, but anyway, here's the link: https://github.com/ItsPietroFelix/itspietrofelix.github.io/blob/master/Ferias%20Frustradas%20do%20Pica-Pau%20%5B!%5D%20(Brazil).md