In Red Imposter Clicker the goal is to get as many points as possible by clicking the Red Imposter. However, just being a fast clicker won't get you the most points. The points you earn can be spent on a variety of multipliers that will give you more points per click. You can also earn extra points by clicking the Golden Imposter that drops down from the sky occasionally.
There are also two bonus modes that are triggered by bars at the top and bottom of the screen. The yellow bar at the top fills faster the faster you click the imposter. When it is filled, multiple Golden Imposters will fall from the sky giving you a chance to get a lot of points all at once.
The red bar at the bottom of the screen fills automatically and activates a bonus mode where you get a x50 multiplier for your clicks. Make sure that you buy as many multipliers as possible from the shop right before this mode starts.
As you play you will unlock skins, backgrounds, and more. However, once you reach a certain point you can choose to ascend. This will reset all of your progress but give you a higher default multiplier so that you can earn points faster. Choosing to ascend is the best choice in the long run.