If anyone can give me any tips on audio syncing, please let me know! When previewing my cartoon on my computer, the animation and audio were well-synced, but, when I watched it after uploading it on Newgrounds, the animation lagged behind the audio towards the end of the cartoon.

I have a few ideas as to what I can do to fix it (which includes redoing most of it...), but I welcome any help! Even though this is just my first Flash, I don't want to just overlook this problem because I'll probably want to know how to sync lengthy pieces in the future!