I tried the diagonals, but the vertical movement speed was doubled if you pushed both up-left and up, for example. I could not find a way to prevent this. You can move diagonally by pushing two direction keys at once.
Cargo bays give you 50 points.
Click on Gauntlet and see.
It is a game mode similar to Ed Marshall's shooter, where the game consists of ever-increasing numbers of enemy ships and the goal is to survive as long as you can.