"Certain checkpoints" refers to specific locations or moments in a process or journey where certain actions or criteria need to be met or verified. Full definition
No, this is not an open world sandbox game, but once you pass certain checkpoints in a level you can not go back and explore the area again. (dailyjoystickpodcast.com)
If both players go down, they respawn at certain checkpoints so players can try again.Jumping and climbing are handled by the game, and depend simply on the direction players are dragging the movement arrow on the screen. (adweek.com)
The levels themselves have a decent length on your first playthrough, but you do have the option to save after certain checkpoints if you need. (dualpixels.com)