It may come as a surprise that Black's position is so bad (at least I was surprised), but he has little play against White's plan of Bc2-Rae1 and opening the center with e3-e4.
1. d2d4 Three main pawn moves are equally acceptable. 1... e7e5 A bold move that doesn't seem quite right. 2. c2c3 A bit timid. 2... d7d5  3. d4e5  3... e8e5  4. h1g3  4... f8g6 A very strange move but not so bad as it looks. The knight has no squares from h8, but the point of the move will become clear soon. 5. f1d2  5... d8g8 Surprise $1 The weird types of castling are one of the highlights of freestyle chess. 6. d2f3  6... e5e7  7. e1d2 Also preparing castling, but this isn't the best. 7... c7c6  8. d1g1  8... f7f5 Necessary to bring the knight into play. Black solves his problems. 9. e2e3  9... h8f7  10. b2b3 Preparing the development of the bishop and also c3-c4. 10... f7e5 Very natural, but surprisingly the knight will be attacked, and White achieves an advantage. 11. f3d4 Attacking the pawn on f5. 11... g6h4  12. f2f4  12... e5g4  13. c3c4 With a series of strong moves, Nepomniachtchi undermines Black's position. 13... d5c4  14. b3c4  14... b8d6  15. h2h3  15... g4h6 