Ah man, if youre getting these scores now, then im gonna get smoked when I tell you this....
Theres another difficulty level, called nightmare, which I think unlocks after you beat level 13.
Its always irritated me when long term players say 'the real game really starts when you hit the level cap' but thats what I feel about nightmare mode. I know the game well but still cant figure out how to even survive some levels.
Now whats this you say about cargo deliverys for higher scores?