tapion, make sure that you're setting it for 60 or so frames and then when you save, make sure you name it something like "randomname.gif". Then, make sure you select the option "save as animation" after hitting ok.
Sproojeh, the first 'tree head'... just for kicks, try inverting it, and messing with the hue adjustment... it'd be interesting to see it in black and orange, or black and red or something.