Bulls and Cows

Bulls and cows is an ancient puzzle game of password cracking.
Now, we make the process of this game more concise and interesting. Take advantage of limited opportunities to guess a random four digit number. Every time you guess, you can get a prompt about whether the number and position are correct, until you guess the correct answer (victory), or use up all opportunities (failure). According to different difficulty and guess times, corresponding points will be obtained.

Game mode
In simple mode, the answer does not contain duplicate numbers.
The hard mode may contain repeated numbers - which will greatly increase the difficulty and, of course, obtain higher points.

Achievements
Unlock new achievements after obtaining certain points or completing specified tasks.

Leaderboard
You can check your best score ranking among all players at any time.