Pick anything and be asked it cold, whether or not you owe it. Nothing here is unlocked by anything else.
Chapter 1
1.e4 e5 2.Nf3 Nc6 3.Bb5 Nf6
13 decisions · 3 rounds of 5
Chapter 2
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6
176 decisions · 36 rounds of 5
Black plays 4...Nf6
130 decisions · 26 rounds of 5
Black plays 4...d6
57 decisions · 12 rounds of 5
Black plays 4...Be7
43 decisions · 9 rounds of 5
Black plays 4...b5
77 decisions · 16 rounds of 5
Black plays 4...Nge7
10 decisions · 2 rounds of 5
Black plays 4...Bc5
11 decisions · 3 rounds of 5