I think it sounds Japanese because of the mallet sounds. The descending mallet sound in the first track, the rocking chair arpeggio in the second, the mallet melody at 2:32, the melody at 3:46 sounds especially Japanese to me (closer to the pentatonic scale), the tune at 4:54 just totally reminds me of Streets of Rage, which is very Japanese, and the last tune has the same pentatonic-sounding thing going on for me in the sax towards the end of the video (and sorta sounds like Contra III: The Alien Wars to me, which is also very Japanese).
So... yeah. I think it's those mallet sounds, coupled with your melodies seemingly never taking jumps of more than two or three steps. You kinda stay close to going up and down the scales, which sounds Asian to me (think of the melody to "Cherry Blossoms" and the Chinese tune - what's the name of that, anyway - it's China's Theme in Super Dodge Ball).
Not a bad thing. Some cool stuff in there. Glad I listened. Keep up the good work!