Feel free to ask questions about the jam here!
This thread is locked because there was a rule change on 28/3/21 which is
You can now use any colors in the greyscale. (Any colors in between black and white)
That said, transparency, gradient, and anti-aliasing is now allowed.
The main reason behind this is because I just found out that there is another jam out there called 1-bit jam that coincidentally have the exact same limitation as us (using only the colour black and white), and theirs are starting first. I hope this will cause as least inconvenience as possible to all, and hope everyone will feel more comfortable and happy with this change.
As there are some outdated information here, please use and refer to this new thread instead.
Though there are exceptions: if it is used purely for the purpose of making a shape/image look less jaggier and it is not obvious, then it is allowed.
(both on the right are not ok)