http://en.wikipedia.org/wiki/Lemmings_%28video_game%29
http://en.wikipedia.org/wiki/Lemmings_2:_The_Tribes
http://en.wikipedia.org/wiki/All_New_World_of_Lemmings
http://en.wikipedia.org/wiki/Lemmings_Revolution
I know, they're wikipedia links, but they were the easiest to find from one consistent source.
First off, I'd work a little more on the lemmings themselves, because lemmings need arms. Before you start on the BGs, I suggest you make the lemmings variations (in the case of L2 and ANWoL) as well as all their powers. The best reference of the games above is probably ANWoL, because it is still 2D and has 16/32(I can't remember exactly)-bit graphics. Also, use a lighter background if the lemmings are going to be that dark.
http://en.wikipedia.org/wiki/Lemmings_2:_The_Tribes
http://en.wikipedia.org/wiki/All_New_World_of_Lemmings
http://en.wikipedia.org/wiki/Lemmings_Revolution
I know, they're wikipedia links, but they were the easiest to find from one consistent source.
First off, I'd work a little more on the lemmings themselves, because lemmings need arms. Before you start on the BGs, I suggest you make the lemmings variations (in the case of L2 and ANWoL) as well as all their powers. The best reference of the games above is probably ANWoL, because it is still 2D and has 16/32(I can't remember exactly)-bit graphics. Also, use a lighter background if the lemmings are going to be that dark.