Thanks for your comments everyone. I've not checked this in a while so I'm sorry for the late reply! To answer a few questions:
• I used videos instead of gifs. The quality for full colour gifs isn't very good compared to videos. Videos are a much small file size too.
• It would have been great to add audio, but the company I created this for didn't have audio enabled on their devices.
• I did start working on a blog but I've not had time to continue it. If I find time to add some tutorials I'll post a link to it here.
• I can't share the source files for this course I'm afraid. The company I created this for owns the IP.
Also this course ended up being a finalist at the Learning Technologies Awards 2019 in the Best Learning Game category!