The EOTB games run very poorly.

1) They are tiny on screen.( not full screen )
2) They are very laggy.

Any ideas how to fix these issues ?
It's a real shame they haven't been worked on to make then run better ( I know they can't look better )
Which leads me to ...

3) Do GOG offer refunds on games you have just purchased and are unhappy with ?

For the first question, try pressing Alt+Enter.

for the second question, try increasing the number of cycles. (For example, press Ctrl+F12 a few times while the game is running.)

Also, if you encounter long waits (like load times), holding Alt+F12 will enable turbo speed.

Can't help you with EOB (btw, which OS? Windows, Linux, Mac? PC, laptop?), but as for 3) they will offer you a refund if you have technical issues with the game that can't be fixed with their help. Not sure if that case applies here, but you can try. They will first try to suggest solutions though and only offer a refund if they don't work. There is no general refund policies for games you are unhappy with, only if they really don't work the way they should on your system, even though it meets the system requirements.

DOSBox emulation is quite demanding, so if your rig is old or low end, it might not always run that well, but try the cycles suggestion by dtgreene.

You need to find the best configuration for your computer or your tastes.

I use 1280x720 res for windowed in my 1366x768 desktop
for full screen I use opengl, normal3x, aspect ratio false, and "desktop" resolution ( you can use deskop, 0x0, or the res your system uses. It´s the same). This last config is important to not have the tiny screen in full screen mode.

Hi, many thanks for all your replies, I really appreciate it.

I have now set the game as follows, and it is now about 90% of my screen size in a window ( I use a 40" HDTV)

Screen res= 1920 x 1080
Opengl
Normal 3x.

With the above settings the frame rate is fine and the game very playable.

I have also tried the "pixel smoothing" options of hq3x and supereagle, but these just make the screen shrink to around 1/3rd screen size. However, I do like the pixel smoothing effect they have.

Does anyone know of a way to keep the big screen with the pixel smoothing effect ?

I run EoB II (1 & 3 also) @ 1920x1200, full screen (aspect is not perfect, but I don't care as this is my native resolution.) The games fill my 28" screen.

I've attached my own .conf file for you to look at if you want--it should give you some ideas about what's possible. I use dosbox svn-daum for some minor shader support that helps some older games look a bit better, as well as a 64-bit version of dosbox.exe. Just remove the .jpg extension I put on it to get it to attach here in these forums and this should show the kind of thing that is possible. Also, I use a single .conf file, just as GOG used to do before they started getting modular (and now use 2-3)...;)

Help! In Eye of Beholder 1, I am stuck in level 9 in a room. I fell from level 8. The only doors open from the other side.

Once you entered the room, there should have been a hole in the floor, that allows you to drop down to level 10. That hole can be closed IIRC and if you did that, you might very well be trapped.