If you have been entering your Central Mainframe Access Code in each day, here is what you would have gotten:
Day 1: +3 attack
Day 2: +3 defense
Day 3: +10 (!) Health
Day 4: +3 stamina
So far, so good! The +10 health from yesterday was really unexpected. Between the past 4 days, the Central Mainframe has given away the equivalent of 19 skill points, or almost 4 level ups (though 10 health is not quite as good as 10 attack or energy).
Not a bad deal at all. If you lost your code, readers have reported that by e-mailing Zynga you can get a code replacement in short order.
Edit for some frequently asked questions:
1. I am unable to get my code again.
You only get it once. Write it down. What I did was save it to my desktop in a .txt document so I can copy and paste it in.
2. I do not see the place to enter the code.
This pops up on the home page every now and again. You can only enter your code every 24 hours. Be patient.