Yes they are quite fun, I wish I was skilled enough to do one myself.
Oh, my friend is Mike AKA *ZaetaK. We did a few collabs earlier this year, but then he got too busy with his own projects to do so anymore so now I just do my own concept art, without anyone else's input. It's more lonely that way, but at least I'm learning valuable drawing skills.
You just finished one with your Minecraft Creeper mech, eh? ^_^
But seriously, I think you're well on your way. Practice when you can, study from reality, and try deconstructing other artists' pieces as well. You'd be surprised at what "active observation" can do to expand your repertoire.
And yeah, ZaetaK's got quite a gallery, particularly with organic-type work. It is a bit of a shame that time is limited for many of us these days to collaborate, but I agree that independent work helps develop one's own voice too.
I REALLY dig the play on hard and soft edges in the first one. The shading adds some nice dimension and definition to such detailed lines. It benefits the right image too, but I feel like it's over-saturated or in a harsher lighting, which kind of clashes with the light background. That said, the coloring really brings your stuff to life. Nice work, man.
Thanks! I'm actually a bit surprised that you like the first one for such a reason, but thinking about it, it's true since it was a rougher coloring experiment. The second one was an exercise in forcing myself to use saturated colors, and I see what you mean by conflict with the background. Gonna have to work at this balancing problem for next time.