How many games are in the Half-Life series?
2
3
3
3
3
5
2
3
5
4
2
3
5
4
2
3
5
4
2
3
5
4
2
3
5
4
2
3
5
4
2
3
5
4
2
3
5
4
2
3
5
4
6
2
3
5
1
4
6
2
3
5
7
1
4
6
2
3
5
7
1
4
6
2
3
5
7
1
4
6
2
3
5
7
1
4
6
2
3
5
7
1
4
6
2
8
3
5
7
1
4
6
2
8
5
7
1
4
6
2
8
5
7
1
4
9
6
2
8
5
7
1
4
10
9
6
2
8
7
1
4
10
9
6
8
7
1
10
9
6
8
7
11
1
10
9
6
8
7
11
1
10
9
6
8
13
7
11
1
10
9
6
8
12
13
7
11
1
10
9
6
16
8
12
13
7
11
1
10
9
6
16
8
12
13
7
11
1
10
9
6
16
8
12
13
7
11
1
10
9
6
16
8
12
13
11
3 games
4 games
128
3 games
128