Nice!Many old cassette music game soundtrack was released, but I also did not see Parodius this one.
In Japan there is shop called Geemu Tanteidan in Osaka which heavy focus on gaming music. Also they arrange game music party once in a while. I did not check of OST for MSX (I do not interest very much in cassette music now haha). But if someone go Osaka it will be a nice shop to explore for music!