Eh. A good time waster, but certainly not much of a puzzle. If someone only has 4 seconds to comprehend what they're looking at, what they're supposed to do, and then go about doing it, you can certainly bet they're going to optimize speed as much as they can.
Yet many of the games actively go against intuition and punish the player for using speed. Strange layouts, twists and turns, unspecific directions of 'when' to press buttons, etc.
If someone has such a short time to do things in anyways, the least helpful thing you can do is make them wait even longer to double check their thought process as to what's actually going on.
A great way to have improved it is not to kill off the player for making mistakes or ramming into things, but only for the time running out. Second, make the tracks and games more linear and straightforward, with more obvious intentions as to process.
As it stands, it's less of a puzzle and more of a kinda-skill game.