I used to play a game on the PS2 called “Monsters, Inc.” and it was a generic platformer with tiny little objectives. Is it possible to replicate a game like this in unity easily?
Yeah, you can make all sorts of games using Unity.
It won’t be easy, but it’ll be fun.
I wish there was an easy way of making a platformer in Unity 
Because this specific game was never ported to the PC, so I decided I should just make a replica of it. And I wanted it to be an exact copy of it, down to the level design. But are there any game engines I could use to accomplish this goal? And what about making a crazy taxi type of game? Is that easy?
One, No, it won’t be easy. Making games isn’t “easy”. Rewarding? Yes. Fun? Yes. Easy? Nope.
Two, read this.
Then I guess I won’t make one, will I? Thanks for the support.
Seeing as how we know nothing about your level of experience using Unity, and how “easily” is subjective, it’s impossible to answer your question. I would urge you to try to make a replica using Unity. You’d surely learn a lot.