I notice that the itch.io system will put your game shown on the "new & popular" tabs for roughly 3-4 days. (that's what happen with my game) Beg me the question, if I already have 500+ downloads on the old game, is it risky for me to update my game? Because I can get 500+ if I create a new game, but I don't know what happens if I just update the already 500+ download game.

Creating a new game would be against the rules. Posting a “Major Update” devlog should bump your game back up.

The comment above is correct. Trying to game the system in any way is against the rules. If you made an update for your project, then upload it as an update and make a devlog marked “Major Update”, which will cause the project to be reviewed by an admin, and potentially re-admitted to similar lists as when the project was first uploaded.

Guys, I feel guilty already by the answer.  lol

I ask this on the forum because I have no intentions of cheating the system. This is purely just sharing my experiences. So to summarize the answer, if I upload new files for my game and create a dev log that marks it as a "Major Update", it'll have almost the same logic as uploading a new game. Thank you for the explanations.