The weather mechanic was mentioned as a feature prior to release but apparently never made it to the final copy. Aside from that, this game is truly the worst Open World design from a AAA company I have ever seen. This games "open world" is simply a linear Halo mission with no checkpoints so you can freely walk from one area to the next. You cannot even fly over mountains or scale to the top of buildings because of all the invisible walls and limits. The only way to enter from one area to the next is through some narrow passage. It's quite pathetic. BUT in it's current state they could still do so much more to bring it alive. Here is a thread I made way back to contribute to this: "Massive AI battles" https://www.bungie.net/en/Forum/Post/152078841/0/0 Note: I have not played TTK, so I cannot say whether it's improved but from all the gameplay I've seen, it's pretty the same thing.