I have been using a Unity animation to update the alpha property on 2D Toolkit Sprites to have them fade out. It has been working great. This morning, I updated to Unity 4.1 and the fade out is very flickery. I'm not sure if this is a Unity thing or a 2D Toolkit thing. I haven't done any experiments or anything yet to determine more. I just wanted to post to see if anyone else has noticed this. I'll look into it more tonight and I can provide video or samples or whatever if needed.