This should be fun ๐ฅ ๐ Consider these all bad ideas. We can keep adding to the pile and see what we like @devnook
image header
The app doesn't content a lot of graphic design in the homepage. What I love about the current version is it's very Google.com like in simplicity. The downside is that it doesn't contain too many images we could optimize ๐ We could introduce an image header, similar to what is done for blog.google:
logo
The app currently doesn't have a logo. If we didn't want to go for the image header approach, we could use a logo (uncompressed, too large) and use that to talk about optimizing images and remind folks to consider SVGs.
As a note: We're not allowed to use "Google Doodles" or "Doodles" in our app title but might want to come up with something short and fun before I/O. e.g "For legal reasons, this app is called Oodles because its oodles of fun and doesn't get us fired, which is also oodles of fun".
carousel
The way you've currently implemented the carousel is clever in that we don't go preloading the rest of the carousel entries ahead of time. One thing that could be optimized is the main Doodle that gets iframed in as interactive. If it's loading a lot of third-party content, we could suggest folks render a static image of the third-party content with "click to start".
images with content
We don't have a lot of editorial content in the app right now. If we wanted, we could have one or two "featured" Doodles where we even pull in some of the Google-created content for those games. One example is the content for the "Doodles Halloween" experience, which had lots of larger images:
https://www.google.com/doodles/halloween-global-candy-cup-2015
lazy load images
In the "browse by year" views, I've used the images returned by the JSON feed for each year's list of Doodles. We could do something where we lazily load those in that are below the fold (or say, only load in the top 3-4 and lazy-load the rest) if we think it would improve performance.
Use animated GIFs somewhere
Some Doodles include a preview in an animated GIF form. We could use this to highlight how an MP4 using <video>
would have been more efficient (and we'll have a Lighthouse audit for this in time for the talk).
YouTube video
A common performance issue I see is folks embedding YouTube videos, which, while they don't autoplay can still load a lot of JavaScript in. We could show how to just use a static screenshot of a video with click-to-view to avoid a user paying for this upfront.