Check whether your sdcard is fake, as @BuZz suggested, I think that's most likely the issue here.

@ClassicGMR That's another rule: "Never do anything stupid without a backup (including not making the backup)."

Ok I understood what was happening.
There were two more optional Dreamcast emulators that I missed installing.

The games that were not booting in the Reicast run well on the other two. :)

@mitu I ended up figuring it out (by accident), I had 2 partitions on the SD card. Even though there was only one named root it was confusing the system. I was using the image for pi 0/1 and had imaged the card with Win32DiskImager.

You mean instead of starting EmulationStation on boot ? If so, then edit the /opt/retropie/configs/all/autostart.sh file and add your own command before the emulationstation #auto line.
To determine which is the correct command line, you can use either the advice from the Docs or just start your game, then open /dev/shm/runcommand.log and see the actual command line used to launch it.

@LiveFreeDead
Okay, I understand that. Thank you for the replies.

@MaMikee Or this one
two thoughts auto boot retropie into a game or into a slideshow
Recently asked

Hello and welcome to this forum.

Please provide us with all of the information that is asked for in https://retropie.org.uk/forum/topic/3/read-this-first to help us pinpoint the problem.

@deadherring Looks fine. ApplePi Baker will write the image without the need to format (I don't think it knows to format the card).

@mitu ok. I don't know how, but I'll look it up

@buzz
As I said above "I had to unplug and repower it up, then Retropie won't reboot?"
Therefore, getting any kind of log is not possible.
This person seems to have the exact same issue I'm having so I didn't think it would hurt to jump on the thread.

I'm trying again today, with a new Retropie, and I'm repeating the same issue. I'm taking your advice and being very patient a giving it plenty of time...

Yes,,, I think it's doing something.... I got a black screen now.... I'm being patient... it's not doing anything except being a black screen for a few minutes....

SUCCESS! I hit the "b" button and Retropie is there.

Thanks for your help.

For anyone else that is having this issue i have discovered the solution.
install retropie 4.0 rather than 4.3 and simply update the setup software from on the pi rather than when mounting the micro sd card.

@tylerx Retropie Manager is an unofficial addon and people seem to be having many issues with it. I have used it though - did you follow this?
Also,

Please do not post a support request without first reading and following the advice in https://retropie.org.uk/forum/topic/3/read-this-first

which you agreed to do.

@shareef Thanks for sharing your solution.

Thanks very much

@Mr.-Pig you can't just extract the image to the SD card. Read the documents on this page on how to install. You need to write the image to the SD card so it becomes a bootable disc. This is basically the first thing in the documents. It looks like you haven't read them at all.

nvm it fixed itself