There weren't any news on this for quite a while, but I've PMed with Vangar who is in contact with the author. The problem with this thing here and at DCEmu UK was that it's WinCE based and near impossible to port to KOS. Anyway here's Vangar's reply:
Do you got any word from Taxman about the progress with Retro Sonic ?
DCEmu UK would now support a release even if it's using Windows CE.
I know he is still working heavily on the project but there has been no new releases as such. I will ask him next time if he is planning a release again soon.
Ah, that's good news! I'm relieved
I tried to email him several times but didn't get any reply. - Thought he would have abandoned the project and the Dreamcast port... >_<
Tell him that we now do support his project, no matter what development kit he is using
Can't wait for the next version
I finally got onto him.
(11:43 PM) = Vangar = - I'l: well the moderator seemed keen to know more about it so he asked me, lol
(11:43 PM) = Vangar = - I'l: hows it going?
(11:46 PM) (d)Taxman(d): a lot has been done since that last DC test, but i haven't been able to work on it for like a month heh
(11:48 PM) (d)Taxman(d): so did they have a discussion about wince or something?
(11:48 PM) = Vangar = - I'l: no idea, the admin pmed me
(11:48 PM) = Vangar = - I'l: i guess his interested in it
(11:50 PM) (d)Taxman(d): but yeah, umm there's some screens floating around
(11:50 PM) (d)Taxman(d): of the special/bonus stages and EGZ boss
(11:55 PM) (d)Taxman(d): http://www.sonicfangameshq.com/forum/sh ... 87&page=31
(11:56 PM) = Vangar = - I'l: That looks awesome
(11:51 PM) (d)Taxman(d): http://www.sonicfangameshq.com/forum/sh ... 87&page=44
Hehe, hopefully you enjoy those screenshots he posted there =P.