I'm going to keep track of bugs and issues people have noticed in this post. If you find anything, please post it here and I'll edit this post.
Emulator issues & bugs noticed (updated for the current Regen v0.77):
Windows Version:
-Turning a cheat "Off" doesn't disable the effect.
Confirmed
-Loading Save States may sometimes lead to corruption.
Confirmed
-Savestates don't work with Virtua Racing (technical limitation)
Confirmed
-Regen can't read and use SRM files created and used in Gens and Kega.
Confirmed
-Loading a ROM from the Load ROM dialog then loading a cheat for the game, causes the Load ROM window to open at the Cheats folder, not the ROMs folder. Possible Vista-only issue.
Needs To Be Confirmed By Others On Vista
Sound Issues:
-In Sonic 3 (And Sonic 3 & Knuckles) when the aircraft appears to drop bombs on you at the end of zone 1 act 2 there are some clipping artifacts in the audio. This occurs using both the 44100 and 48000 sampling rates and the SuperHQ setting has no effect on it either.
Confirmed
Non-working games:
-Ya-Se Chuan Shuo (Ch)
Requires Extra Hardware
Linux Version:
-No GUI yet.
-Slowdowns *can* happen.
-Using key direction combinations like up+left/up+right/down+left/down+right causes the main directions to not respond until a couple presses, nor are those combos supported.
Also, I'm going to keep track of feature requests in this topic...
----------------
GENERAL
----------------
-ROM Browser. Based off Gens32's ROM Explorer.
-TAS features: movie recording with re-recording support, frame advance, etc.
-Various development and hacking features (VRAM, palette, sprite list, and VDP registers view, YM2612 and PSG registers view (and YM2612 registers dump), enable/disable VDP planes, etc.)
-Full 68k debugger with breakpoints, traces, etc (Gens KMod or Gens Tracer for example).
-Cheat code finder. Like the one Kega as, but enhanced to use the debugger as well (if needed).
-Automatically save and load Cheats for games (based upon the naming scheme of the ROMs, like Kega).
-Editable cheat window interface. Meaning the ability to add/delete selected cheats (New Cheat & Delete Cheat buttons), and edit (Edit Cheat).
-Cheat window remembers it's position when opening it.
-An option to to control how much the screen is brightened with a sub-menu and adjustable by certain percents.
-IPS patch support (with a customizable directory for this via the config)
-Separate configuration settings for sound related things, like directories and adjustments to games that have issues.
-Kega's netplay with the ability to play with Kega.
-Support for the Sega VR via disassembling the VR tester ROM.
-Support for the Sega Pico tablet and pen.
-Ability to load a new game over an existing running game.
-Ability to "remove" the game cart while the game is running.
-Ability to use up+down and left+right key combinations.
-7zip ROM explorer (ability to pick which ROM to open from inside a 7zip archive.
-Custom message font with size and color.
-The ability to dump music as GYM (with a directory set up to do this).
-Support for custom windowed/fullscreen sizes (like Gens32).
-The ability (via a Tools sub-menu called "Sprites") to selectively disable sprite layers and backgrounds, and to put sprites on top).
-Add Kega's Preferred Order country function to the Country selection (may need to split off the Country menu as a main menu for itself, again like Kega). This will help some users whom want to change the auto detection order.
-Ability to set certain functions (like Turbo Mode) to gamepads, with the ability to toggle turbo mode on/off with a gamepad.
----------------
GENESIS
----------------
-Support for the Genesis BIOS (with some toggle to enable/disable it in the config).
-Unique directory for the Genesis BIOS file (BIOS/Genesis?)
-Game lock-on support via a "Load Lock-On" menu item to choose up to 4 ROMs to "lock together" as one game. Examples of 2 are Game Genie + a game, or Sonic & Knuckles + Sonic 3. An Example of 3 locked together games are Game Genie + Sonic & Knuckes + Sonic 3, or Sonic & Knuckles + Sonic 2K UPMEM + Sonic 2. An Example of 4 locked together games are Game Genie + Sonic & Knuckes + Sonic 2K UPMEM + Sonic 2.