What's the catch are the games deleted from the Wii U's storage after 30 days?

January: Balloon Fight (available now!)
February: F-Zero
March: Punch-Out Featuring Mr. Dream
April: Kirby's Adventure
May: Super Metroid
June: Yoshi
July: Donkey Kong

$0.30 / £0.30 each.

I'm only getting Super Metroid.

So Balloon Fight offer is only available for a week?

To answer my own question. No, each deal is available for 30 whole days...

Source

• 

  Balloon Fight (NES)

  From Wed, 1/23 to Thu, 2/21

• 

  F-ZERO (SNES)

  From Wed, 2/20 to Thu, 3/21

• 

  Punch-Out!! Featuring Mr. Dream (NES)

  From Wed, 3/20 to Thu, 4/18

• 

  Kirby's Adventure (NES)

  From Wed, 4/17 to Thu, 5/16

• 

  Super Metroid (SNES)

  From Wed, 5/15 to Thu, 6/13

• 

  Yoshi (NES)

  From Wed, 6/12 to Thu, 7/11

• 

  Donkey Kong (NES)

  From Mon, 7/15 to Tue, 8/13

That's a nice little promotion. Super Metroid for 30 cents is a ridiculously good deal considering its greatness.

Every single one of those games is a good deal. Seriously, 30 cents is chump change. But to be honest I expected something a little bit more front loaded, to get people to buy the Wii U now.