It was one of the first assemblers to tokenise source code as it is entered, along with MAC/65 for the Atari 8-bit computers, similar to how many BASIC implementations work.
[4] The previous year Crystal Computing had released another machine code tool for the 16K ZX Spectrum called Monitor and Disassembler that could be used in conjunction with Zeus.
[5] Sinclair User and Big K highlighted the program's ease of use for beginners,[3][6] while also being a very powerful tool in the hands of an expert.
[3] The necessity of exiting the assembler in order to save any generated code was cited as a potential drawback, especially for beginners.
[3] In 2008 Simon Brattel rewrote Zeus under the same name as a cross-assembler for Microsoft Windows together with integrated emulator and debugger.