So ok. I have now finally finished my fourth song for the PSG. I call it HARDY.
Previously I have played around some with hardware envelopes but mostly to create interesting bass sounds. This time I wanted to explore if it was possible to use HW for lead instruments and effects in the upper frequencies, mostly because this is more difficult. I wanted this tune to sound "not PSG" so I aimed for non standard sounds wherever I could fit them.
I found out that I could indeed use a small range of 4-5 notes in the upper regions if I detuned all other instruments by 1-3 semi notes. This of course limited the melody a lot so I had to be really creative with how I used the instruments and how I could "hide" the fact that I needed to use more notes than the ones available as HW.
My main concern at first was that since it's only possible to play one HW sound in one channel at a time I needed to create a SW bass that was pretty thick so I took inspiration from Jeroen Tel on the C64 who often used bass sounds that alternate between octaves at an uneven rate and it actually worked surprisingly well with the PSG square waves too.
One fun thing about HW sounds is that most of them sound like rubbish but some of them come alive when adding slides to them which easiest can be heard in the dubstep sections and at the very end of the song. However it takes a lot of time and experimentation to find sounds that work.
My biggest discovery is probably the ending sound heard at the 03.00 mark. This is a cyclic HW sound that actually fades out. This is NOT easy since you can't control the volume of HW sounds.
Big thanks to Def Danny who has been available during this whole creative process with feedback, suggestions and ideas. I really appreciate it.
So, here it is. Hardy - a pure PSG song without any samples or tricks. Should be possible to play with a MSX1 even.
Please listen with LOUD volume 
Perhaps the song is a little more style rather than substance and some notes are maybe a little sour but I think I managed to pull it off relatively well and create a tune where the HW-sounds doesn't sound like shit all the time :)
Have fun... and please feel free to write a comment or two.
P.S. So why is this my final song for a while?
Well, I'm creatively empty at the moment. I need some time to recover. This was a VERY exhausting project.
Hard to believe what can be achieved today, since my first impressions when using the first PLAY "CDE" in BASIC (some 35 years ago). I like it! The music. The creative approach. And the endurance to go the full length to complete a song with these tricks! 
