On my PC, there are no visible markers (I'm assuming you mean gave-save checkpoints like they have in the latest Tomb Raider games).
On my PC I can save anywhere at any point. I may not restrart exactly where I saved but it's in the general area (though in Gloria's Theater it's not close enough).
When you go back into a game, you'll notice that there are 5 gamesaves to choose from. There is also, at the very top of the list of gamesaves, the most recent Auto-save point. I'm assuming these are the unseen autosave check-points in the game.