What to do with a game:

I was wanting to make a game that already exists, but improve the graphics and add stuff to it. But it looks like a lot of people have already done that. And they've done a fine job of it too.

I don't really understand your question. Do you want to copy a game? Or do you want to find a good beginner's example?

Just make a game, a new one for now.

It's best to keep this one a secret, my project, or anyone else project. It's a good idea for us all to keep our projects a secret. Otherwise everyone else will have the same idea and copy it. Then making that game would be obsolete. Unless I can still make it different than others somehow.

But on second thought, it would be fun to collect many people's versions of "asteroids", or "super Mario" or whatever. It would be quite fun to collect (buy) many people's version of the same game. Rather than waiting for the next episode (or part 2 of the game)

They can add some humor into it.

Many people are making spoofs of Star Wars, and it's still funny and entertaining. So many different versions.

-There are also parodies of popular games people enjoy playing.

Maybe I should just make a parody of a game people enjoy playing.

It doesn't matter. It's easy to create ideas, but the hard part is actually building the game.

One of the best things a beginner can do is take inspiration from other games and essentially clone them. It helps them understand the amount of work that goes into making them, and provides a blueprint so you don't get lost with your "greatest ideas"..

You'll also have a higher chance of finishing the game.

Also, I wouldn't worry too much about being secretive about ideas- because why would you limit yourself to just a handful of ideas when you can literally make endless ideas. Chances are somebody has already thought of whatever it is you are thinking of anyways.

Also, you can't really afford to keep things secretive as an indie, especially if you don't have much experience, because you need to build an understanding of what will be successful if you have any serious goals. If you keep everything secretive, you might just find out later that your ideas weren't as great as you think they were, etc. So you might spend more time on something than was necessary.

Those are just some suggestions.