EDIT: I just realised I never included the data files with the binaries..oops. The tar file of the source code has them and the binary if you still want to try i
for anything pixel related, i like aseprite. You can get the source code on github for free or buy the built one. But its really not hard to compile yourself.
also on an unrelated note, im looking for where the theme is announced, i havent found it :p can someone point me in the right direction