I’m in for the second time,

Engine: Unity 3D with Futile http://struct.ca/futile/ it’s a code focused approach/ or Rage Pixel

Sound: BFXR (http://www.bfxr.net/)

Music: Generated: http://www.ludumdare.com/compo/2010/12/14/for-those-of-you-who-cant-make-music/

Art: Unsure http://www.midnightfragfest.com/sprite-editor/

http://www.ludumdare.com/compo/tools/