[Simon]

Do you mean that these are all free public domain Flash games that anyone can download for themselves at no cost? So what you've done is just spent the time downloading them and putting them in one archive, and what you're doing is just selling the service you've performed?

Depending on the exact copyrights covering the 600 games, you may or you may not be able to do that legally. Do you have the copyright statements on file somewhere so we can see what restrictions may be in place? If you've researched and documented the copyrights, and there are no restrictions on reselling them packaged this way, then you may have a product worth what you're asking.