General opposites:
* Sequentially: This implies that things happen one after another.
* Successively: Similar to sequentially, suggesting a series of events in order.
* Individually: This implies that things happen separately, not all at once.
* Separately: Similar to individually, focusing on distinct actions.
More specific opposites:
* Consecutively: This emphasizes a specific order or sequence.
* Gradually: This suggests that things happen over time, not instantly.
* In succession: Another way to say sequentially or consecutively.
* In turn: Similar to "one at a time" or "individually."
The best opposite for "simultaneously" will depend on the specific situation and the meaning you wish to convey.