void CheckHiScore()
{
int hiScoreExp = PlayerPrefs.GetInt("HiScore", 0);
int sessionExp = mutationManager.GetSessionExp();
int currHiScore = hiScoreExp >= sessionExp ? hiScoreExp : sessionExp;
hiScoreText.text = "" + currHiScore;
PlayerPrefs.SetInt("HiScore", currHiScore);
PlayerPrefs.Save();
}