I admire the work of Masao Tsubasa on Metal Gear Acid; it's not an easy thing to play second fiddle to Yoji Shinkawa, doing art for an MGS game.
Studying some of the concepts here I was a reminded what a deceptively light touch many Japanese artists bring to their concept work--obviously they produce a lot of finished images, a lot of press images, but as a game developer I'm more drawn to the simple, workmanlike but extremely accurate/elegant colored line drawings. You see this style often in Japanese game design, even for design related to films or television shows.
Below is my own MGS-alike design with a few different attempts at color schemes. It's a rough first outing, the quality of the linework just isn't there yet. But I'd like to continue in this style for certain illustrations; once I master it, it'll be a lot faster way to produce concepts that meet certain needs.