Why is 1.e4 e5 2.d4 Qh4 a blunder? In Lichess, this sequence is rated as a blunder. However, black can take the pawn afterwards without white being able to prevent it (3.Nf3 Qxe4), so it seems like a good move to me.
Furthermore, if white makes the mistake to move 3.g3, black takes the rook (3.Qxe4+ 4.Qe2 Qxh1).
[FEN &quot;rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1&quot;]

1. e4 e5 2. d4 Qh4 3. Nf3

This (Blitz) game of mine caused my confusion.
I would not go so far as to call it a &quot;blunder&quot;, but White is getting lots of compensation for the pawn. They get a big lead in development and Black's queen can be attacked.
Here's one way it could go:
[FEN &quot;&quot;]

1. e4 e5 2. d4 Qh4 3. Nf3 Qxe4+ 4. Be2 exd4 5. O-O Nc6 6. Re1 Be7 7. Na3 Nf6 (7... a6 8. Bxa6) 8. Nb5 O-O 9. Nxc7 Rb8 10. Bb5 Qg6 11. Bxc6 Bd8 12. Ne5 Qf5 13. Bf3 Bxc7 14. g4 Nxg4 (14... Qe6 15. Ng6) 15. Bxg4 Qf6 16. Nd3 *

It's also worth pointing out that White can keep things nice and simple if they choose, and not give up the pawn:
[FEN &quot;&quot;]
1. e4 e5 2. d4 Qh4 3. dxe5 Qxe4+ 4. Qe2 


Furthermore, if black makes the mistake to move 3.g3

The computer is never going to care about what happens if your opponent makes a mistake - it always assumes your opponent will play the best move.