[Intrepid Homoludens]

Lynsie has a good point. If you want to 'diversify' your market (and potential fan base) to include non-broadband users, find alternate ways of distribution. One way would be the 'old fashioned' method of fulfilling orders by sending cds over the mail. Another would be to keep the game exclusively downloadable but to have the otherwise huge file segmented into several smaller packets that could take just 30 minutes to download on a dial-up connection. The user would have to wait a while (a day or two) to get the entire file, but once she has it she has it.

If the dial-up user switches computers, you could advise them on how to transfer all the data from their old system to the new one, or they could simply re-download the game (if they're patient enough).