Love what's goin on here. You've clearly got a grip on the shapes, colors, and language of this style. Also, I just love that you drew the main character of my favorite game in my favorite graphic style, lol.
Some general ideas if you want to keep messing with this style:
-Try making the background more dynamic! Not sure if this is raster or vector but if you have a program like Illustrator you can make some really neat stuff by just messing with shapes and the transform tools. When I've done stuff like this, I mimic a lot of Kentaro Mori's work, which combines a lot of type with graphic elements and occasionally photographic elements as well.
-I'd love to see this piece or something similar be a bit more in-your-face perspective wise- I love what you're starting w/ the shoulder bolts, but having the headphone spike seem more pointed at the viewer or putting a hand in view could add a lot of energy.

Overall though, love this. You nailed the style and I hope you create more! BTW, some great inspo I can recommend to you would be the Pictoplasma books and the book New Species.