In my language, I refer to them as the core mechanics or pillars
The most important mechanics for this game are…
Movement: the way the rocket moves.
Camera: The player needs to see where they are going. It helps if the camera movement is smooth so it’s seamless and pleasing to the eyes.
Fuel depends on how fast or slow the fuel is used.
I could have said powerups, obstacles, end goals and shooting, but those are easy to build, so I didn’t count them as core mechanics.