Clunkier. Yep. Doesn't look near as good as the 'real' Spectrum R-Type.

https://www.youtube.com/watch?v=-6lvAXSGBpI

I think it's the blocky movement that kinda kills it for me.

Perhaps I'm missing something but the video you linked to seems to have blocky movement as well.

Some of those sound effects are AY-8192 sounding to me, explosions on the spectrum were never like that.

They added an AY chip to the Spectrum starting from the 128K model I think. It was also available as an add-on to the original 48K.

The Spectrum 128 contained an AY-8192, so you are right on the money. Earlier models were beeper only.