It looks way too bland. Right now it just looks and feels like its the entrance to a japanese garden.
Only because of the background i might know that its an amusement park, but even then, i only knew what those things in the background are because i know what the challenge is.
You should put up a flashy sign, add some balloons, people, fireworks!
Whatever works to get that amusement park feeling!
Good luck.
i agree with the others, it needs more work. if you yourself say it looks unfinished, then it must be.