A lot of the time, the C64 and Spectrum/Amstrad ports were done by different companies, in isolation. You’d often see the C64 go its own way, changing up levels and gameplay. While the Amstrad port was usually a lazy port of the Spectrum. You can often see the colour limitations of the Spectrum ported across wholesale to the Amstrad as well.
In the case of Commando, the Spectrum and Amstrad teams had some overlap and the games share some of the same DNA (see the title screen, for example), while the C64 was distinct. It doesn’t feel like a lazy Spectrum > Amstrad port though, so it has that going for it. The C64, as usual, feels like its own thing.