Thanks for that, this is proper old-school.
Two things: The CDs also include a bunch of demos of other games too (and Blitz Basic!). There may just be an old favourite there for you. Just had a grand old time revisiting GFK's "Hole In One" and getting +9 after two holes, and getting smashed in Double Top. Good times.



The other thing is that a lot of Blitz/Blitz3D games seem to run like absolute arse on modern systems (Win10 specifically). This didn't
used to happen in my experience, but now they do; I suspect the shiny new gfx cards and drivers. I first encountered this with Wiebo de Wit's amazing
Thrust Deluxe, which still kicks arse to this day (highly recommended). Nevertheless, they're unplayably slow out of the box.
That's where
dgVoodoo2 comes in.
Download that bad boy, copy the .dll files from its MS/x86 folder to the folder of the old game (or demo) you want to play, and
voila! You should see a dgVoodoo watermark in the bottom right-hand corner to let you know the game is running through it. You'll also notice it's not running at 3fps anymore, which is nice. No installation, no mess, no fuss. The defaults should work great for almost everything.
If you want to tweak it a bit though (eg maintaining ye olde 4:3 aspect ratio on a widescreen monitor without having to fiddle with nVidia/AMD gfx driver settings) then you can do that in the
dgVoodooCpl.exe file. You'll want to focus on the 'General' and 'DirectX' tabs for the Blitz/3D stuff. In the DirectX tab you can also turn off the watermark if you don't need it anymore. Once you've done your tweaking, copy the
dgVoodoo.conf file (a human-readable plain text file) into the same game folder as the .dll files you copies earlier, the the .dll files will pick up the configuration changes you just made.
Hope that helps someone. Now if you'll excuse me, I have some 20 year old Blitz games to revisit.

PS: I didn't have any luck at all with Windows' "Compatibility Mode". More power to you if you do, but the above works great.
PPS: Happily, this seems to be related to the 2D stuff specifically. G-Tok (3D Defender clone) worked a treat.