Normally, pressing Escape on the keyboard will close any open UI elements and eventually open the main menu. The main menu is where you save and it happens to also pause the game (in single player). Imho a much more convenient pause than the old shift+space or the new "pause" key on the keyboard.
However, I recently ran into a situation where repeated presses of Escape did not, as expected, lead to the main menu. Instead I was caught in a loop that I had to break manually.
How to reproduce:
- Factorio version 2.0.17 & Space Age
- Place a tank or spidertron on any planet
- Tavel to any space platform with your player character
- Open remote view of the planet with the tank/spidertron and open their UI
- Start to drive tank/spidertron remotely and close their UI
- Press Esc on keyboard without ending the remote driving. This takes you to the remote view centered on your character on the space platform.
- Press Esc on the keyboard again. This takes you to the remote view centered on the tank/spidertron, showing "entered vehicle" floating text.
In contrast, when your character is standing on a planet, the step 6 brings you to your character and the step 7 opens the main menu.