How familiar are you with the CD-I in general? Don’t get me wrong, I like the system but there’s no way I’d pay the prices for those rare games. CD-I software lacks any kind of copy protection, so pretty much anyone can burn discs if you can find the files. I’ve heard of some convincing repros too, some being passed off as originals. There is one seller on eBay that has tons of CD-I titles, he sells a lot of repros of prototypes that look very professional.
Prototypes of pretty much all consoles are very easy to copy If you collect those you really have to know what your doing ps1 dreamcast ps2 It's all the same.
I mean seriously though considering that most prototypes are pretty much blanc discs with some text written on it it is kinda hard to prove when it is legit or not I mean even legit prototypes look home made non professional especially in the early stages
Prototypes of disc based systems are all easy to fake since the original isn't that complicated to begin with not to mention games easy to burn. It is far more easy to fool someone with prototypes than with reproductions legit games there are no specifics when your looking at prototypes It's all guess work what sort of equipment and materials would have been used at that point in time.
In allot of cases it is an employee who worked on the game who sold them for people to fully believe when it is 100% legit.
Are there any legit repro's of full games with manuals boxes and discs with full art of the zelda's etc now that is a repro if that were the case.
prototypes of carts are allot harder and you will need a certain investment but even than you could take a worthless prototype and put some rom inside put some stickers on it with a nametag of a nice game to make the value skyrocket.