On the following page of the Crash Bandicoot 4 guide, you will find about the Retro Mode. You'll find out how it works and whether it affects the gameplay and controls.
Impact on gameplay
Retro Mode has a limited number of lives, if you lose them all you have to reset the level and start over.
Modern Mode has no such restrictions. If you die, the game loads from the checkpoint. However, it doesn't work for a time trial - then you always start from the beginning of the level.
Game modes can be changed at any time. All you have to do is go into the gameplay options and change the mode.
Here, you can also turn on or off the time trial ghost and the character's shadow.
Retro Mode has no effect on the controls.
Impact on graphics
Retro Mode has no effect on the graphics in Crash Bandicoot 4.