Home › Openings › Center Game › Center Game: Halasz-McDonnell Gambit Center Game: Halasz-McDonnell Gambit, Crocodile Variation ECO C21 · 1. e4 e5 2. d4 exd4 3. f4 Bc5 4. Nf3 Nc6 5. c3 Practice this opening · Play against the computer