I'm not really good but I'm still learning
Hey, we all have to start somewhere, and I see a ton of potential. You definitely understand shading and use of light (particularly on your X 23 piece). Just keep practising, study some books on anatomy and keep working at it, you'll get there, trust me.
How long have you been drawing?
Nice, yeah as @Mad_Wolverine: say, its good that you take the time to make shadows etc. Im not that good myself, but my problem is when drawing is that im too lazy to shade and stuff, which i really should start doing because even though my drawings may not be the best its crazy good training.
Anyway, nice job... i envy you that youre so good at finishing up your drawings.