Click on the button as many times as you can. If you don't click on it for 1 second or more or click on something else, your combo resets. The time left to click the button to keep the combo up is shown as a bar at the left, and the combo is shown below it. The closer to the center of the button you click, the higher combo you get. Once you get to 100, 200, etc. the button will shrink. Also, this is just the 1st version, made in 1 day, so bugs are possible and likely. Bugs found: If you click on something else other than the button, the combo doesn't reset. (Happens most of the time, half-major gameplay glitch) Whenever you click on the button, colo(u)rs show up for a frame. (Always happens, minor graphical glitch)
Credit to Scratch or something. (I just realized I haven't shared a project for so long.) I got to 674 on v1. Proof: http://cubeupload.com/im/EyqD8R.png