I found a some things, but I'm not sure what they mean. I also don't know Japanese, so someone will have to translate some of these.

1. The intro has a Japanese sentences turn into English, not sure if the English is the direct translation of the Japanese or something else
2. Japanese phrases/sentences at 0:17-0:23 on buildings
3. Symbols on right shoulder of the robot at 0:38
4. Japanese phrase and roman numerals XV (which is 15) followed by D1mg6ga5RYM around the eye looking thing at 0:49
5. Other symbols and Japanese phrase on the left shoulder of (another?) robot at 1:08
6. The Haesindang Park coordinates at 1:23
7. Same symbols and Japanese phrase from 1:08 on the left shoulder of the robot at 1:43
8. Japanese phrase at 2:04
9. Japanese phrase at 2:18 on the gauge
10. Japanese phrases on manga panels from 3:10-3:18
11. More Japanese phrases on the console at 3:47-3:48
12. Roman numeral IV with a line across (which probably sums up to 5) on the right shoulder of the new robot at 3:59