Little Guy. Marcus is correct. The code is real. I have verified it personally.
It is called the KONAMI CODE, named after the company that made Contra.
Apparently a developer named Kazuhisa Hashimoto put it in during testing so he
could play through the game without dying constantly, and then simply forgot to
take it out before shipping. Or chose not to. Either way: our gain.
The full sequence, entered on the title screen before pressing Start:
↑ ↑ ↓ ↓ ← → ← → B A
Up, Up, Down, Down, Left, Right, Left, Right, B, A. Then Start.
You will begin the game with 30 lives instead of 3. It works on the
NES version. I cannot speak to other versions as I have not tested them,
but the Society takes accuracy seriously.
This is what is known as a cheat code — a secret input sequence
that unlocks hidden functionality the developers left inside the game.
They exist in many games. Some are known publicly, some are discovered
by accident, some are apparently left in by tired developers who simply
needed thirty lives to get through their own level.
The code has since appeared in dozens of other Konami games, and at this
point I suspect it will outlive all of us.
Re: blowing on cartridges — the jury is still out. I believe it is mostly
placebo, but I also believe in doing whatever works.
-- Beatrice
Sysop · Keeper of Useful Information
P.S. You're welcome. Go beat stage one.