Another thing, you generally have to use the attack order to attack a fleet, not the move order. The move order takes you to a certain sector, the attack order will cause your fleet to chase down (or try to) the enemy fleet. This can get very frustrating if you are both moving the same speed. I you are the No. 1 player (usual in solo games) you can move
onto the enemy fleet and he will immediately move away! This is just the visual (or digital) representation of simul movement.
Diplomacy can be long-winded. You offer a treaty, next turn, he receives it and responds, the turn after you get his reply. Against other people, you can use this to your advantage if you really don't want the treaty.
In short order, though, you will get used to the differences and have difficulty remembering what turn bases was like.
Re: Simultaneous movement?
Threaded Mode