It's a pity that there is no original 0.53 version available (for so long already) - while the current state of the emulator is absolutely impressive. That means people who are interested go for the cracked version. I like to pay for it (again, I will from day 1) but when a new version (the upcoming 0.6) is released, I'm afraid there will be people pretty quickly to crack it again. CD-i member cdifan, the author of CD-i Emulator, discusses what is the best way to go: A free CD-i Emulator or an Open Source CD-i Emulator
...CD-i Emulator might be more profitable when you set up a donation platform with extra features, like on Patreon. I'm all for an open source version though, it would be a huge loss when you would disappear suddenly and no-one can take over the work. Perhaps work will go faster when more people are able to contribute (not sure if that is possible - I like the MAME version as well because I can run it on Retropie, but it is not very user friendly to set up and the compatibility with cd-i titles is pretty poor. A combination of the best of both would be awesome.....
...To me Open Source, 30$ is cheap (i plan to buy the next proper stable release), but there's a few areas of concern with closed source: -Others can't improve / lend a hand -When you die all the work is gone and won't be upgradable to new architectures as a result (ARM is the future). I'm putting this bluntly but it happened to a Nuon emu dev so his legacy is toast -can't be made to run with retropie etc... - According to CD-i member Seventy7
Retrostuff has an interesting view on this: "The current alternatives [to CD-i Emulator] are: 1) To use an F/OS emulator (MAME) that seems to be too hard to set up for the majority and (depending on the version) suffers from slow-downs in some of famous games or 2) to go to certain sites and download a cracked version of your emulator or 3) to use actual CD-i hardware. Even though I only use it only very rarely to test a system ROM file or to make a screenshot for comparison, I'd like to pay for it and have a legit working copy without time bomb (and/or crack). After all, you've put a lot of work into it and also distribute code and knowledge to the open source alternatives."
Would it, pure theoretically, be possible that you integrate the functionality of CD-i Emulator into the MAME version to boost its compatibility? Would you, theoretically, be able to solve the current problems MAME CD-i Emulator is having...?
cdifan: "CD-i Emulator is basically a set of libraries with a single "application" project using them, though that doesn't mean it would be easy to integrate into another product. I've been working towards an SDL version for years, as well. Me integrating the functionality of CD-i Emulator into MAME is nigh impossible for a variety of reasons. The codebases are just too different, both in architecture and in style, and the MAME people are (rightly, in my opinion) quite adamant in their wishes here. I personally do not see the point of it, either, you'd just be adding the disadvantages of the MAME UI to CD-i Emulator. Compatibilty fixes would be possible, but it requires interest on the MAME side and I haven't seen that in recent years. Also, I'm not really sure cdiemu is better in title compatibility, it didn't use to be, I've got some work there."
[Thanks, cdifan, retrostuff, Seventy7]