If we have another option E as:
E: Upload the game files to an S3 bucket and grant public read-only access and use CloudFront to serve game files requests.
How do we order the options?
Probably depends lots on the use-case, but I’d probably put this at #2 above the EC2 option as data outbound costs are slightly higher with EC2 than with CloudFront. You might get better download times for some customers given the global distribution, but I would still choose the BitTorrent option as #1 because I would hopefully offload some of the outbound data cost onto the peer network.