This forum does not get a lot of action and I wanted to post a list of roms that are not playable to me or have issues. If somebody finds this useful than great. More so it's for me to keep track of games that don't work and so I can remove them from my shield eventually. The list will be compiled slowly as I play through games. Feel free to let me know if you do not encounter the same issues as me or if you have an issue with a game. If I have the same game I will try it out and then add it to my list.
My setup is 2017 Nvidia shield with roms stored on a 2tb WD external HD using 3.0 usb connection. I run retrox app always updated. All roms from old retromania forum unless noted.
Game / System
issues
Army Men 2 / N64
pixelated opening screens but fine during gameplay. Some spots suffer from horrific slow down and delayed controls. Sound quits halfway through the first level and never comes back. Retrox app quits after the third level and you can not play any further than that.
Silent Scope / Dreamcast
the scope site is distorted. Game is not playable.
Army Men / Dreamcast
graphical glitches and low resolution. I say low res because it's very hard to see things in the distance. Maybe this is how the game actually was. Sometimes tanks and enemies seem to disappear and reappear. Lots of background popup, again may be how the game was. It is playable though.
Decap Attack / Genesis
Controller button do not function properly. I tried configuring the controller again and same issue. Jump button will jump and pause the game. Game is not playable.
LOCO ROCO / PSP
Game will not load. It kicks me into the ppsspp menu. Which is really odd since I've never seen any emulator menus before running my setup.
Sonic Adventure/Dreamcast
Game resets when using tails on stage 2 casinopolis.

Vay / Sega CD
Game starts up fine but you can not skip any cut scenes. The game often goes black. The music still plays but the screen will be black. Sometimes it comes back but after a minute or two. Sometimes it doesn't. Seems to happen when entering and exiting a cave or battle. At this point the game is unplayable.
Skies of Arcadia/ Dreamcast
Game plays well. Few graphical glitches especially on the menu. But about 2 hours into the game you need to hand over a passport to proceed. The game just resets. No way to move forward. I was enjoying this game so much. Hopefully a way to fix this.
After trying several times and giving up I went back a day later and attempted to get past the crash part again. This time instead of reading the text I mashed the "A" button to skip through it quickly. Some reason I was able to continue the game. I will update as I go.
Grandia II / Dreamcast
Game plays with graphical glitches popping up once in awhile. Alot of the time on the compass when walking around. I eventually gave up on this one on RETROX because I decided to finish other games first. I picked it back up with another emulator and beat the final boss. This game after beating the final boss you play as one character and run around and talk to the other members of your party. Well my rom (i think) must be no good because I can run around but I'm stuck in one section. The screen will not rotate or advance to the next section. So watched the credits and final text on youtube since not worth trying to fix for the last 30 seconds of the game.