I want to be able to download the game so I can record videos more easily and so it's fullscreen but there doesn't seem to be an option for it on the itch.io page for the game.

You might be able to download the JS file and sprite file and run those, but I'm not sure how exactly you would do that. The links are here if you want to try that out: https://v6p9d9t4.ssl.hwcdn.net/html/5787627/html5game/CT4.js?FJGYB=476241618

Wow, looks like there's a lot of unused assets in there!

The game itself is designed to work on 800x600 ratio, and doesn't work on fullscreen. The best you can do is run the game directly in this link: https://v6p9d9t4.ssl.hwcdn.net/html/5787627/index.html

Then you can change the zoom of the browser window, and also resize the window to fit the game-window size.

Also, you could download all game files and make a stand-alone version on your computer; but it will be really hard for you if you don't know what you're doing. There is no reason for you to do so either.