There is a difficulty slider you can adjust pre-game which affects the number of points that are awarded per kill. The slider goes from 0% - 100%: The slider level determines the percentage of points that are awarded.
From this thread where the question is noted(albeit mistyped):
Ran 2 games on Barricade warehouse for 5 mins. One at 100% difficulty and the other at 50% (default)
At 100% i scored 21.5 million
At 50% i scored 14.1 million
Both i had auto XP as first perk.
Hope this helps!
Okay, so, again from the Steam forums:
I can probably guess what caused that: the tweaking of the difficulty level and the amount of Xp you get per kill.
When Nation Red was released a lot of
players said it was too easy to
collect perks: The difficulty level
was then increased (apart from new
perks, bosses, weapons, etc. which of
course also affects scoring) so it
became harder to beat existing scores.
Players felt NR became a bit too hard:
the Xp per kill was increased.
So what you're seeing is some scores
achieved with an 'older' version of
the game and some with the current
In the end the game is constantly
evolving with new weapons, perks,
player classes, etc. It's impossible
to keep the scoring perfectly equal
(some new boss may be a bit harder
than others, some new perk may be a
bit too powerful, etc.)
Resetting leaderboards is one fix but
I've tried to resist doing this until
no new perks/bosses/player
classes/weapons, etc. are added.
The next update will be a major one
with 3-4 player coop and the final
player classes. If a leaderboard reset
is needed, that may be the best time.
Having said that, if you want to beat
You get a lot more Xp playing on higher difficulty than lower
You get more Auto Experience (Perk) on higher than lower difficulty
On higher difficulty, zombies spawn more often = more Xp.
So beating existing scores is very
possible but maybe try not to
investigate the exact playing times,
etc. when comparing scores.
Hopefully this helps. :)