When in doubt, do a job instead of doing anything else. The pay reward is higher than the ore you would have sold otherwise... Coolant is the most valuable upgrade to buy, when in doubt. Lets you go deeper for the higher priced gems!
My suggestion - always take the customer's order as a priority over everything else... the food can wait without spoiling (or so it seems) - so no reason to waste the waiting points! Also, better to side on under/over mixing if that means getting that extra order into your queue. Great game!
The best defense is a good offense... plug 2/3 of your points into Attack, and the remaining 1/3 into Vitality. Every 3rd level add a point to Stamina instead of Attack, and you should have no issue. Makes battling much easier!
 "Utopian Mining"){kind=icon}
 "Papa's Freezeria"){kind=icon}
 "The Legend of the Golden Robot"){kind=icon}