No, the rules are pretty simple. The one who manages to first cross the finish line wins. Everybody knows the rules.
The problem is it is not a very simple sport and there is some game theory involved. Riding as fast as possible is not the best strategy, actually it is pretty poor one.
The better strategy comes from understanding you don't need to win by a lot, winning by 1s is the same as winning by 10 minutes. Also riding alone or at the front costs a lot more effort than riding behind somebody.
Actually, riding at the same speed at the front might be max effort and in the pack might be almost coasting.
Together, this means you may have a very valid strategy to try to preserve energy (ie. keep with the pack) and count on your better ability to sprint at the end to get ahead of competitors. That of course as long as you believe there is nobody running away.
At the extreme of effort, very small differences of effort can have very large effects on your body. If you look at it, a difference of tempo to run a 5k and 10k is very small.
The current world records for 5k is 12:35.36 and 10k is 26:11.00.
If you look at difference, 5k is 151s/km while 10k is 156s/km, just 5s or 3% slower.
And yet that minute difference lets you run twice as far.