How do I make circle decrease?

How do I make a circle decrease like in the game Chrono True Color? Can someone explain me or send a capx file? Also, I can't understand how they randomize the color and the word, can you please help me with this too?

My suggestion would be to use an animated sprite and just show the certain frame when needed.

frostyelk can you be more explicit please with your idea? Also, I thought about using After Effects for making the animation, but the problem is that I do not know how can I use that animation in Construct.

In After Effects you can export the animation by using "Frame by Frame" to png. That will render each of your frames in AE to a single PNG file that you can import into Construct2 as a animated sprite.

Then you can just set the sprite to play that exact frame you need when a certain condition is met.

If you apply the HSL (Hue Saturation Light) effect to a sprite, you can animate the color by using a Sin expression for the Hue parameter (parameter 0). If you want to randomize the color, simply use the Random() expression for the Hue parameter instead. You can of course also change the S and L parameters, but you quickly end up with a lot of very dark graphics if you don't limit the values corretly..