Hello,
The ZX spectrum core is great and it looks correct, but on some games the sound/music is not accurate. The developper's website
http://www.mike-stirling.com/r…a/zx-spectrum-on-an-fpga/ says "Cycle accuracy – there is no memory contention and the CPU core doesn’t match the timing of the real Z80."
Do you know how it could be improved? Is someone working on this?
There is a link to a lot of ZX games and tools.
http://www.worldofspectrum.org/
I never used and never seen a zx spectrum in real life, but i will try the core. the games are looking interesting. I will try it today oder tomorrow evening. 
Let me know which game i should try.
Some games I like:
Thanatos: http://www.worldofspectrum.org/infoseekid.cgi?id=0005218
Abbaye des morts: http://www.worldofspectrum.org…nt/769312/#Comment_769312
Uroboros : http://www.indieretronews.com/…take-on-snake-for-zx.html
More recent and awesome games are there:
http://www.indieretronews.com/p/zx-spectrum_28.html
Castlevania is amazing. Pentacorn is nice too.
Now about the spectrum itself, there are two ways of getting music. Originally, it was using 1bit music using the beeper (internal speaker). It was quite versatile even if the sound was quite raw. It also allowed to play music on 4, 6, even 12 voices! A good example: https://www.youtube.com/watch?v=T42WuUpBuHE (Agent X, by Tim Follin). On the MiST, it will play, but as it's quite CPU intensive, it would be slowed down a bit.
The other way for having music on the spectrum is the use of the AY-3-8910 soundchip (also used on Amstrad, Atari ST, MSX....). It was an addition to the spectrum 128. It would allow to play (3 voices max) music during gameplay since the generation of sound was done on an external chip. Some examples: https://www.youtube.com/watch?v=QhsaziIz4Mg . On the MiST, it sounds ok, yet not as faithful as we could expect. For example I've just noticed it's monophonic, while on the original hardware it's stereophonic (one voice on the left, one on the right and the 3rd one on both). I think it's because it's using the YM2149 code for Atari ST, and on Atari ST it's always monophonic...
I just tried the core. The ZS Spectrum environment seems to work, but i cant start any images. Maybe a wrong format? There were only tape images, they might not work, i dont know. I will try it tomorrow again.
Oh yes, there are plenty of great games for the Spectrum. My favorite speccy-game is "Ant Attack". I have to try out Castlevania, i read that it's an impressive game for the Spectrum.
@Kris: You can load tape images with the MiST in 2 ways: With ESXDOS (but you have to install it forst). Then you only have to press the virtual "NMI"-button, choose your game and play it. With the standard-core (without ESXDOS) the "tape" loads in original speed. But then you have to type in LOAD "" first (at the spectrum keyboard the keys "J", then "AltGR-P" "AltGR-P". It's a bit tricky, especially when you never used a real spectrum before 
