Skip intermission sequences:
Hold L + R + click Left Analog-stick + click Right Analog-stick during an intermission sequence.

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.

Better mechs:
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.

Hint: Stage 1: Recommended camping location:
Go to the first stage on rumble (the city) and climb onto roofs for a good camping location, if you get high enough. Make sure you have a slingshot to shoot from the roof.

Hint: Stage 2: Recommended camping location:
In the second stage underground, there is a large round room with a ramp that spirals down the wall. At the bottom end of this ramp is a nice location to camp out underneath. Even better, an ammo, health, and New Yen drop point is directly in front of you when you hide here.

Hint: Stage 3: Hiding location:
Jump onto the "high rise" in front of you when you first enter the level. Jump up there and walk around to the left, then look around. You should see a passageway for you to pass through. Go into it halfway. This is a good location to let O.C. recharge or wait.