VirtualBox: Seamless mode has nothing to do with what disks you use. For gaming, seamless mode is not even recommended. You will need to game in full-screen, in a window or in Scale Mode: best to be able to stretch the screen. Full screen does not stretch and only the host native resolution will look good (older games will most likely not be able to use that and will be small and centered with much of the screen unused).
VMWare Player cannot stretch the screen (the same problem with small centered image as mentioned above). VMWare Workstation has something called Exclusive Mode which is best for full screen games: they will look natively. Storage is not important; Real disks in VM's are for advanced users only: one small mistake and you will format the wrong disk or loose data (on VirtualBox is even more difficult on this aspect since you assign real disks through command line). Use virtual disks and they're safer.
This theoretic discussion won't solve this thread's problem: is best to test things out and choose what works best for you.
I've seen some games work better in VMware Player (Dune 2000, Age of Empires) and others on VirtualBox (Red Alert 2). Testing it out is necessary.
Actually both full screen mode and scale mode sucks. Stupidly full screen doesn't go full screen. Scale mode scales without keeping the aspect ratio (well, you can play around in non maximized mode to keep the ratio), also I prefer not to see the window frame and desktop elements while playing....
Yeah, I know that.
Fullscreen isn't fullscreen... but just because the virtualizartion software isn't able to tell the host graphics or OS to switch to stretching, something that Workstation's exclusive mode does.
So in order to achieve what you want for instance on VirtualBox (yes full screen is still possible: some extra clicks are needed) you will need to:
1. look at the game's resolution when in fullscreen.
example: older game has 800x600
2. note that game's resolution (here in example 800x600) and set the host system to that.
now,
if still needed stretch the screen (some newer systems don't do that anymore by default
Here's what I see: fullscreen is not fullscreen neither on the host.
Fix for Intel HD cards: go to a lower resolution (800x600 works for this) and then the stretch option will be available in the picture above.
3. now that the host resolution is set and you are in real fullscreen, go to the VM and set it to fullscreen.
4. Since the fullscreen on the host (can be even lower than 800x600 if needed) is the game's resolution => the game will be in real fullscreen even in the VM.
5. Recommended:
disable the mini toolbar in VirtualBox so it will not pop up and annoy you when the cursor is on that screen position.
Exiting the fullscreen will still be possible with the (default) shortcut: Right-Ctrl + F
This works very well and is not hard to do (what I don't like is that the Desktop icons get messed up on lower resolutions but that's just temporary).