I really wanna make a game clashing all my favourite 8 bit platforming games and it would save me a bunch of time just using sprite sheets on the internet for the game, am I allowed to do this? If so, do I have boundaries on what I can do with my game etc.?
The question is easy to answer: No, you are not allowed to do this. The use of other peoples property always requires a written consent, and only those people can grant you rights like using them for commercial use.
In almost all cases you will have to pay for a licensed use.
You can, however, wait until something falls into public domain. It is hard to tell, when exactly this happens, but as a rule of thumb the life of the original author plus 70 years. I'm afraid this is more of interest for the next, or next next, generation of game designers