Eric, could you please check your email, if you have received my emails? I sent you a reply yesterday, but today when I wanted to write a new email for you, I noticed my email has disappeared, it cannot be found from "sent" folder either, and I know it was there yesterday. Just want to make sure you know I am buying that cartridge! 
Please tell me here, if you have got my email(s) after your first reply? Just in case there are problems with emails, thank you.
Thank you, I will check my email next. 
@MäSäXi,
not for the C64 but for the MSX 
I would
remove the dithering on the background and then make twocolor sprites with no blackframes.
The player could get a third sprite for black pixels, low priority sprite that just disappears under load, not adding to flicker.
I study very well the way to do the graphics for Uridium, it is a fact that, if you want to put a background on MSX1, you will have visivility problems with lighter colors. Then, I decided to:
- Make dither in the background, when the scroll moves, the dither part change to a single color(color mixing), a new darker color for MSX1. In the game, you don´t see the dither when you play, only when you stop the scroll you can see it. This effect does not work on youtube video.
- The black shadow of the sprites make possible to see them on lighter backgrounds (yellow and grey).
That is the reason I decided to make in this way.
Actually we did also two alternative versions of the background using in one case solid colors, in another case alternating solid colors (like in hap's 25 colors scheme).
This is a sample of the the version in solid colors
These are test levels in solid colors and "hap" 25 colors
Just compare the sound of games like Dragonslayer VI, Fire Hawk, Starship Rendezvous, Valis II etc. with their PC88 counterparts, and I think it's pretty clear who wins.
Definitely
Thank you a lot for that, John! I can hear that there´s some (very little) difference which is not because of 'lesser' AY-chip (which can be called your very own style/arrangement) and I can hear your japanese influences too. I don´t know if anyone else can hear that but I can.
It is true: I added some manual reverb + detune + chorus, pitch bends, 'ghosting' and 'vibrato' to make the whole thing a bit more 'lively'; mainly in order to compensate for the loss of a synth like SID (which natively has some of those effects in the presets and filters). Although I would probably still have done some of those things, because, indeed, that's how I tried to give the song a bit more 'spice' and 'swing'.
And yes, I couldn't help but including the little 'drum fill' at the intro, but that was not just to make it a bit more 'exciting' but also to mask the 'singing around' of the HW envelope frequency.
So I really wonder where the Japanese influences are, because I, myself, cannot hear them. I'm innocent! :D
About (very very slight) japanese influences, I just got such a feeling while listening your arrangement, nothing more. Please continue making arrangements of Commodore 64 game tunes for our AY-chip. This Uridium theme tune was a good example of what you can do! Maybe someone gets interested in making actual game around your C64 arrangement.
As someone said this Uridium is just an overgrown tech-demo, I really hope we could see and play more overgrown tech-demos based on Commodore 64 games. 