>>77852031You start off in Smallville, as a young Clark. This is the tutorial stage of the game, where you learn about your powers, and at the end of the stage you face of with your first villain, get your costume and the ability of flight.
When you fly upwards, you go to an overmap where you can go to different areas; the first you go to is the Fortress of Solitude, which is where your alternate costumes and other extra stuff is accessed, like cutscenes.
You then fly to Metropolis, where the real Superman shit starts going down. During the course of the game, you get points for doing different acts of heroism. Early on, there isn't much danger from enemies, as your invincibility starts to grow stronger. Soon enough (around the point where the player is getting a little cocky and complacent) Lex Luthor is introduced into the storyline, and you start to fight enemies who have Kryptonite, and also must do harder tasks to save people that villains like Luthor or Toyman set-up.
There is also an element where the storyline is fluid, depending on what you do at different times. For example, you can fly to Gotham at any point after the initial Metropolis section. Whatever time you fly, you have to do a boss fight with Batman. If you fly over early, it's trivial and easy, but if you leave it until late, he will have prepared, and it will be far more difficult.
I'd say that the final boss would also be dependent on your actions throughout the story.
That's just a brief outline that I came up with off the top of my head to justify a slow increase in power level, rather than you starting off at full power.