a little bit of progress on my wild claims about making an Ico de-make.
i have a lot of work to do concerning the background. this will be one of those projects that makes me a better pixel artist, because i'm having one hell of a time working with four colors. 
yep it's quite a challenge. Glad to see people are doing such great submissions.
1 point that most people seem to forget though... even though you've only got 4 colors to play with overall with the backgrounds; when it comes to making the sprites you should be playing with 3 colours, as 1 of those colors is dropped in favour of the mask... so sprites should actually be 3 colors only... (IF you want to be true to DMG GB) [have a look at those first four samples from genuine GB games and count the colors in the character sprites... everyone is 3]

Tis up to you though, if you fancy upping the challenge? No need to tho as adam says in the challenge rules - it IS optional.