It's simply poor sounds from the sound libraries and probably just wrong ones for some sounds. The original had strings, your one has synth strings that sound more like something from the 80s. You can't polish a turd - you cannot take poor sounds and make them sound good - plus the string thing in yours just doesn't work. The bass is almost missing and the drums sound like a beat box. You MUST start with decent quality sounds. Stick a few clips of individual tracks onto Soundcloud so we can hear the source material. I really do want to let you know that compression and effects will not improve this.
Thank you for the honest, detailed feedback.
I'll try to address each of your points:
1. "The biggest one is the sound source is simply horrible." - Right, I've used a bunch of samples from my DAW. There's literally hundreds if not thousand of samples of a variety of instruments. Some of these came with the DAW itself, while others were purchased by me. It's highly likely that it's gonna take a massive amount of time to find those which sound ok - which I have no problem with if that's the thing you say we should look at first. I'll address this point later on as well.
2. "The drums are very thin and weedy sounding - just not rock drums, let alone metal." I've used my midi keyboard and my DAW (FL Studio) to record the whole thing. The drum samples came from a plugin called FPC. I've uploaded a sample of just the drum track (double kick + snare + hat) for the 0:35-1:00 part of the original song to my Soundcloud account ("FPC Drum Sample Kick Snare Hat"). I've also uploaded a sample from a paid-for drum kit plugin called MT Power Drum kit ("MT Power Drum Kit Sample") that's meant for heavier music. This is just me playing around with the kit - please excuse my losing the rhythm, the sample is just meant for you to offer your opinion as to whether the sound is better (I think it is).
3. "Musically, you are also playing close chords in the left hand - they blend badly and produce that full low end that just lacks definition. If, for example, you play a C chord then just play the C and maybe the G in the left hand, and put the others in higher up." I get what you're saying about the close chords - I'm just not sure what you mean when you say "left hand"? There is no left hand. What would be the left hand part (if I were playing this song on my keyboard) is supplied by the bass and the drums.
4. "If you draw a graph starting with bass to the left and treble to the right - there is no space where there is no instrument - it's everything everywhere, all the time. You need to create 'holes' for the other instruments to slot into. As the left hand space is full, the bass could do anything and you can't hear it." Right. This is what mixing is about, right? Fitting the various elements into their own "slots".
5. "I think you may be going too fast, trying to learn the art of recording too quickly with such a complex song." There's gotta be somewhere I can start, though, right?
6. "What are you using for the sound? It may simply be inappropriate for this genre of music." As already mentioned - FL Studio. I've already talked about the drum parts. As for the guitar, I've used a plugin called Sytrus (with a guitar preset called "Distorto"). I've uploaded a sample of just the guitar part to my Soundcloud ("Distorted Guitar Sytrus Plus Keys"). I've also uploaded a sample
of the thing, though recorded by means of a guitar wave sample pack which I bought ("Guitar Sample Amped"). I ran this through an AMP plugin.
7. "At the start of the second section the snare is on beat 2, but it then becomes displaced as if the melody riff you are playing had an extra note in the bar - quite disturbing. probably worth experimenting with quantisation too - to tighten it up, but I got the feeling you recorded in real time and just couldn't keep up?" I'm sorry, I'm not sure if this is what you're referring to, but the drum beat for the 00:35-1:00 part is different than the one for the vocal part ("Time, only time").
For the former it's: double kick - (1) (e) (+) (a) (2) (e) (+) (a) (3) (e) (+) (a) (4) (e) (+) (a); snare: (1) e + a (2) e + a (3) e + a (4) e + a ; hat: (1) e (+) a (2) e (+) a (3) e (+) a (4) e (+) a.
For the latter, it interchanges between("speeds up" and "slows down"): double kick - (1) e + a (2) e + a (3) e + a (4) e + (a); snare: 1 e (+) a 2 e (+) a 3 e (+) a 4 e (+) a; hat: (1) e + a (2) e + a (3) e + a (4) e + a ; and: double kick - (1) (e) (+) (a) (2) (e) (+) (a) (3) (e) (+) (a) (4) (e) (+) (a); snare: 1 e (+) a 2 e (+) a 3 e (+) a 4 e (+) a; hat: (1) e + a (2) e + a (3) e + a (4) e + a
8. "It's simply poor sounds from the sound libraries and probably just wrong ones for some sounds. The original had strings, your one has synth strings that sound more like something from the 80s" You're referring to the intro part, right?