Scratch

You can create a list called "achievements" and make the respective values of each entry in the list the logic behind whether each achievement has been unlocked. 

Thusly, the game would start with all entries having a value of "0" (or locked) and whenever the conditions for each achievement is met, change that value to "1"  (so if the third achievement is completed, "replace item (3) of "Achievement List" with 1." 

To display the achievements, you can have sprites that check for each entry whether that value is 1, and to show or hide accordingly.

An example is provided here using a slightly different method, there's a list called "remaining achievements" that deletes each achievement entry from the list when it is completed.  The sprite that lists out the achievements checks if that entry is missing, and if it is, it considers it unlocked.

Last edited by Kileymeister (2012-12-17 18:23:51)

First make a sprite with the acheivement show icon and make 2 costumes with it, in fact please check this project out download it and see how i did the acheivements! I am not spamming i am just trying to help him/she!