You can see the visible cuts between frames, having a lower interval would make this a bit better. Remember, it takes somewhere between 24-30 frames per second to create smooth footage. Each picture is a frame, so having more pictures means you have a smoother recording.
The following timelapse is one I did a while back. It's actually three shots per second, but the three pictures were merged into a single frame to create a subtle HDR, so more accurately, mine was 1 picture per second, and it resulted in rather smooth footage. Also, be sure you set your capture size to around 1-3 MP as a 1080P video is actually only around that size, and it will increase the number of images you can store as well as the speed in which they save.