Firstly, this is fantastic! Very well done. Im running this on my Philips VG8235. The graphics are lovely, nicely enhanced but remaining true to the Speccy. Speed: it is significantly faster than the spectrum original and the difficulty ramps up very quickly. Level 3 on this felt like a much later level on the spectrum. Also, the horizon objects are very difficult to hit. They were on the original, but I've only managed to hit a helicopter once and never managed to hit a tank yet... Love the border animation when you crash!
What is the issue with the sound? I've not noticed any problems so far...
Overall, an excellent game. Will definitely purchase when completed. Thank you.