in the big picture, its only a problem if your code exceeds ram.
thank you for the reply, but I don't really worry about "code exceeding ram"(sorry, I didn't state my question clearly enough). my problem is that I need to do many if statement to test whether the player has completed certain achievements, which is unnecessary after the player has completed those achievements. for example
if(KilledTheFirstEnemy == true)
the problem is that a player would complete "KilledTheFirstenemy" in the very early stage of the game, but the if test still needs to be executed through out the whole game which is kinda wasting in terms of computation.