Imagesource: https://github.com/maziac/

To play or work with the Speccy is one thing. (Certainly an interesting one.) But it becomes really exciting when you want to implement real-world requirements on the Z80 CPU of the machine in Assembly itself.

"Does anyone do that anymore" I hear you say? The Z80 is still in production today, That answers the question. Once you warm up to the way the Z80 Assembly works, you'll have real fun with the thing. But the fun also ends very quickly, when you have to distribute coding, assembling, debugging, disassembling, sprite conversion and all other tasks over a whole bunch of different applications. 

The unfortunately unknown author maziak has recognized this problem, and has a solution for it.

DeZog will probably be known to pretty much everyone, who gives the Speccy a proper Assembly treatment.

But for those who don't know it yet, DeZog is a real enlightenment. The VSCode extension has a lot to offer. As a debugger it fulfills all expectations. Standard debugging as you know it, sprite display, performance measurement, disassembly of existing object code, display of registers, stack and callstack ...

If you program for the Z80, you can't get around this piece of software. Prerequisite: VSCode.