I think it definitely should be survive the most rounds/stages. You can survive an extremely long amount of time if you just run around the arena after doing a few safe, successful hits and letting the timer decide "you know what, the player did some damage, the AI did not, so the player wins."
As for difficulty category... I would just do any% easy and any% hard.
What are the rules for Survival? As far as I know it's an endless mode so is the run just who can beat the most amount of dinos?
Why do you deal that much damage in hard at the end of the game? Can someone explain? Because when I play it it doesn't seem to do so much damage?
Example: My PB with EU version = 25:25. My PB with the USA version is 21:58 and I made more mistakes/lost more time in that run than in my pb with the EU version.
For mission 1 my PB was 1:15. On the USA version i dip below 1 minute EASILY.
Both gameplay and the loading screen are significantly faster with the USA version.
Just tested and the USA version of this game is SIGNIFICANTLY faster than the EU version in many aspects.
Don't bother with the EU version if you want to have a competitive time!