As an Euro guy, I started a bit later than everyone else. The theme is OK, not my choice but I came with nifty idea for it. My attack plan is:

• Day one :
  -Start on 9:30
  -Have working game(player controls, loading the world(s), swapping between the worlds, collision) on 16:00-18:00
  -Basic enemies or art for the rest of the day(22:00-24:00)
• Day two:
  -Start somtime in the morning
  -Finish all the levels(or at least most of them) by 20:00
  -Start polishing the game, adding proper graphics, audio etc.
• Day three:
  -Polish, polish, polish, graphics, audio
  -If I have time, add more enemy types
  -Finish everything by 2:00

All times are given in CEST.
Happy dev-ing