Chess Opening Theory/1. e4/1...b5/2. Bxb5/2...Bb7/3. Nc3/3...f5

= O'Neill Gambit Accepted, Lila Attack =

3... f5?!
This move baits the e4 pawn to take on f5, allowing the bishop to capture on g2 attacking the h1 rook.

Here, white should play d3, defending the pawn.

If white takes the f pawn, 4. exf5?!, Black can play Bxg2, and White plays Qh5+. Black's king cannot move, so 5. g6 is forced. If white plays 6. fxg6, Black can play g6. After White captures on g6 to keep the threats going, Black will play Bg7, allowing the knight to be captured with hxg8 in order to gain a tempo on the queen after Kxg8. After the Queen moves, Black will play Bxh1 regaining and equalizing material. Both sides have chances.