For my second LD in compo, I created Pasazh, an action/rpg/adventure like Zelda. It was a little too ambitious for only 48h but I tried.
I used Tiled Map Editor for level design and I programmed it in Java and used slick2d.

What Went Right :
– Graphics, satisfactory for only 48h even if the hero sprites are not very beautiful.
– Level design, I think it’s rather good, I created 19 maps and they are not bad.
– Gameplay / code : satisfactory even if I did not have enough time to create all the features I wanted.
What Went Wrong :
– TitleScreen : no time to create a good titlescreen :/
– Enemies : I wanted to create a boss and more enemies, in particular under water but no time.
– Music and sound effects : they are bad but I don’t know how to compose a good music and I don’t control Bxfr.
My game :
http://www.ludumdare.com/compo/ludum-dare-24/?action=preview&uid=7308

erf, pictures are resizing :/
(PS : sorry for my bad English)