Last week from 23rd to 26th I was on a LAN event called GetOnline, here in Kajaani, Finland. I went there because of the game development competition, which required you to make a game in about 48 hours on Microsoft XNA. And the theme for the game was "platform game with puzzle-solving elements." Fortunately for me, I had recently been thinking of a platform game that would be nice to make at some point and it was perfect for the competition. So I decided to go with that idea.
Skip to 48 hours later of no sleeping, lots of coding and some pixel art, I had the game done. With only one bug left that I was aware of, but it wasn't anything major.
There were total 11 coders taking part in that competition and of which I was the only one to work alone. Which was fine for me as I didn't want to share any possible prizes. >;D
They announced the results of every competition (CS1.6, WC3, ItG etc) that same night. Skip about half an hour of nervous waiting and I found myself on the stage holding the "grand" prize. Yay! Microsoft was sponsoring the prizes for the gamedev compo so I an Xbox 360 and 5 games. Fortunately I already own a 360 so I can make some money out of it and most of the games aren't interesting enough or I already have them so I'll be selling them too.

If you want to try out the game, you can download it from here: [link]
As it's done in Microsoft XNA, you need to have XNA Framework installed and you can get it from here: [link]

You can give me feedback here if you want, as I will at some point continue developing the game. I have lots of ideas that didn't make into that prototype of sorts.

-Update-
Some screens of the game:
Main screen
Level 1
Level 2
Level 3
Level 4
Level 5
Level 6
Level 7