I’ve been experiencing issues with certain achievements not unlocking.
I completed ODST in its entirety on Normal difficulty, but did not receive an achievement for completing all levels on Normal, or Easy. I also did not receive an achievement for completing Tayari Plaza or Coastal Highway. I replayed Tayari Plaza, and the achievement finally unlocked. Then, I replayed Coastal Highway, but the achievement still did not unlock.
Furthermore, I completed at least 3 games of H2A multiplayer on May 9th, and did not receive the achievement for completing an H2A game on the 9th of any month.
Not sure why these achievements will not unlock, and by the looks of some other threads, some other people are experiencing the same issues.
Achievements are integral in motivating the player to continue to play the game and gives us challenges to overcome. When these challenges are not rewarded, however, it can become disheartening.