The game is great for a first! To avoid the jitteryness of the platforms that move up such as the one in the first level, you'll want to use Fixedupdate() instead of the regular Update() since fixedupdate advances with unity's physics engine whereas update just advances based on FPS. Also the installer wasn't really necessary, it also gave me a few errors when trying to install but it worked in the end. Overall, nice effort, keep it up!