First Fight
First twist is that a person can move on to the next layer's ring as soon as he defeats his opponent.
They can just wait their until their opponent comes from their previous battles. This will let the first person rest after their fight and has more time to recover and since they defeated their opponent much faster, they might even be stronger.
So, a stronger person who has more recovery time, is going to be a big problem for an opponent that came late.
Another twist in the environmental set up.
In every ring on the fourth layer, before the fight starts, the two contestants of the ring would participate in a coin toss.
It is done by an elder and would be impossible for both contestants to interfere. The person who wins the toss would get to pick the environment of the ring from the available options.
So based on their choice, a formation will be activated that would create an energy environment.