The Scobee companies will have a special mech with better weapons available on days that are a multiple of six. For example, Day 6, 12, 18 through 60. Successfully complete the game to get a "Clear" saved game. A special mech will appear on days that are a prime number
Easy money
On Day 55, you will have a chance to only fight drones for 3,000 to 4,000 Neo Yen each. It is possible to make well over 3 million Neo Yen through those fights. At the town map screen, place the little "snowboarder" pointer over the garage area. Rotate the Right Analog-stick ten times in any direction to gain 1,000 Neo Yen. Note: You can only do this once per day.
Skip intermission sequences
At an intermission sequence, hold L + R + click Left Analog-stick + click Right Analog-stick.
1,000 NY
When looking at the map, rotate the right thumbstick to the edge of its reach 360degress(you can only do this 10 times a day.) Rotate until you do not hear the "ding" noise any more. This works every day so don't think its a one time deal.
Invincibility
At the main menu, press X, Y, B, A, Back, White, Up, Down, Up, Down.
Better Mechs Upon Game Clear
Once you saved your game (beat the game first!) mechs that appear on days that are not divisible except by itself (i.e., days that are prime number days, like 2, 3, 5, 7, 11, etc. - break out your math book) are super-powerful.
For example, between days 20 to 30, the Wild Mechanics will have a used SV with quad legs, heavy core, and one arm cannon at a cost of 1,500,000.