needs more surprised patrick

On a more serious note, what software are you using to make your poster, cause if it's photoshop I can give you advice on how to smooth shadows, clean stuff up, get up close and personal, etc
Immediate advice would be smooth the shadows as has been said, change the gradient's angle so that there's more shadow in the bottom left than there is anywhere else (emphasis), and either actually use text for the speedkarts word, or don't just copy paste the .gif file so that you get that clipped shadow. Looks silly. Not to mention the top white line you have between BLOCKLAND and speedkarts is distracting
other than that, looks really great for a first poster :) keep up the good work
It's so good that Filipe should use it.
ha