The f-file is closed and the bishop on b3 is no longer so dangerous. Black has a fine position.
1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1c4  3... g8f6  4. d2d3  4... f8c5  5. a2a4 Just the 10th most popular move in this position. All sorts of move orders are possible in the Italian Opening. 5... d7d6  6. e1g1  6... a7a5  7. c1e3  7... c5e3  8. f2e3  8... e8g8  9. b1d2  9... c6e7 This natural move is a novelty. Black wants to move the knight to g6 and play …c6-d5. 10. f3h4 The standard reply. 10... c7c6  11. d1e1 The queen goes to g3, supporting the attack. 11... d6d5  12. c4b3  12... d8d6 This is a small inaccuracy that gives White the initiative. 13. e1g3 The e5-pawn is now pinned and White is ready to make use of this by playing d3-d4. 13... f6h5 A good defensive move, removing the queen from its unpleasant position. 14. g3g5  14... g7g6 This is a dangerous choice. It was better to return the knight to f6. 15. h4f5 This is a rushed move that closes the f-file and allows Black to level the game again. 15... c8f5  16. e4f5 