IT DEPENDS ON THE GAME. BUT USUALLY YES
Yes they are because if they wasn't there would be An endless possibilitys of cheat codes
There are many cheats sites available for your convenience. One site that I am familiar with is faqs.com.
I don't think there are any cheats, you should play through th ess game fairly, it's a lot more fun :)
The first game with Mario is donkey kong. But the first Mario series game was Mario bros.
well there are alot of websites for cheats but depends if your using a consol or computer if your using a consol type in the name of it for instense ps2-cheats.com like that or if it a PC type in PC...