Virtually any characteristic of God can be counterfeited using time travel or technology which can manipulate time. This is not to argue that there isn't a God. Only that God-like abilities are possible by exploiting time. Omniscient is trivial if one can have access to all events in space and time. If rumor can be believed that may be the case right now due to claims that the Catholic church has a chronovisor.
Transmutation of the elements can be one example. Much like turning water into wine (John 2:1-11) modern physics can turn lead into gold using a particle accelerator. An advanced technology could exploit the half-life of an element by manipulating time to make an element break down. If time could be accelerated at the femtometer scale then hypothetically proton decay would occur according to some beyond-the-Standard Model grand unified theories.
The idea that God could revise historical events is not new. Thinkers such as Saint Peter Damian have pondered such an idea hundreds of years ago.
For an example of how God could manipulate time one could look into prayer. The following is account by By Elder Juan A. Uceda:
In 1977, I was serving as a full-time missionary in Cusco, Peru. My companion and I received approval to take all the missionaries in the Cusco zone to the magnificent Machu Picchu ruins.Towards the end of our visit to the ruins, some of the missionaries wanted to go to the Inca Bridge, part of a mountain trail. Immediately, I felt in my heart the Spirit constraining me not to go there. The trail was on the side of a mountain with a 2,000-foot (610 m) drop-off. In several areas the trail was only wide enough for one person to pass at a time. My companion and I told them that we should not go to the Inca Bridge.
However, the missionaries insisted that we go. The pleadings became more intense, and despite what the Spirit had indicated to me, I gave in to the peer pressure and told them that we would visit the bridge but only if we were very careful.
We entered the trail that leads to the Inca Bridge with me at the end of the group, and at first everyone walked slowly, as agreed. Then the missionaries started to walk very fast and even run. They ignored my petitions to slow down. I felt obligated to catch up to them, to tell them that we had to turn back. I was far behind them, and I had to run fast to catch up with them.
As I came around a turn, in a passage too narrow for two to walk, I found a missionary standing still with his back against the rocks. I asked him why he was standing there. He told me he had received an impression to remain in that spot for a moment and that I should go on.
I felt the urgency to catch up to those ahead of us, so he helped me to pass him, and I was able to get a little farther down the trail. I noticed that the ground was full of greenery. I planted my right foot on the ground, realizing, as I fell, that there was no ground underneath the greenery. I desperately grabbed onto some branches that were underneath the trail. For a moment I could see down, some 2,000 feet below me, the Urubamba River, which crosses the Sacred Valley of the Incas. I felt as if my strength had left me, and it was only a matter of time before I could not hold on anymore. In that moment, I prayed intensely. It was a very brief prayer. I opened my mouth and said, “Father, help me!”
The branches were not strong enough to support the weight of my body. I knew the end was near. In the very moment when I was about to fall, I felt a firm hand take me by the arm and pull me up. With that help I was able to continue fighting and get myself back on the trail. The missionary who had stayed behind was the one who saved me.
But in reality our Father in Heaven saved me. He listened to my voice. I had heard the voice of the Spirit three times before, telling me not to go to the Inca Bridge, but I had not obeyed that voice...
Elder Juan A. Uceda tells the story to show how his prayer for help was answered. But at what point in time was the prayer answered? Was it after the words were spoken and the firm hand of the missionary who stayed behind grabbed his arm?
If Elder Uceda had remained last in the line of missionaries God could have inspired one of the others to look back at the right moment to see that Elder Uceda needed help. But humans according to most religions have free will and there's no guarantee that would have happened. There are many stories of times when people have felt like they should have done something but then ignored the feeling only to regret it later. Instead, one of the missionaries waited for a moment based on a feeling to let Elder Uceda pass by. That put the missionary in the position to see that immediate help was required. In a way effect preceded cause and the prayer for help was answered affirmatively before the words were uttered.
Or the missionary who let Elder Juan A. Uceda pass by was really the quantum leaper Dr. Sam Beckett. Remember, virtually any characteristic of God can be counterfeited using time travel or technology which can manipulate time.