Here's my problem; I'm in the Trolley Combat section of Chapter 4. I am just past the part where you see the Panzer for the first time and then there are a ton of people on the left shooting at me. No matter what I do, my trolley always catches fire (if not from the people on the left then from the trolley behind me soon after that). I believe it is a problem with the auto-save, every time I load from the last checkpoint my trolley is in the middle of taking a huge hit (I guess from the Panzer). That leaves my trolley incredibly weak and after only a few shots I am forced to reload. I am playing on Easy and have tried about 20 times, but someone always gets a few shots on me and that is all it takes.
What I'd like to do is be able to go to the main screen and load the level from the beginning of the section instead of loading from the last checkpoint. What I'm afraid of is missing out on any progress I've made towards achievements and towards the endings. I know there are some achievements that you have to complete in one play-through, for example, Soft Touch requires that you disarm 10 traps. This has to be done as you progress through the game. You can't just load the same level over and over and disarm those traps to get the achievement.
So my question is, will loading a level from the main menu ruin any/all achievements and will it negate any moral points I've gotten so far or does it act like an auto-save from when I started that level and all my progress will continue?
UPDATE: I loaded from the beginning of the level and continued on. I was able to unlock the "Soft Touch" achievement (Disarm 10 wire traps), after disarming one more trap. I'll keep updating with cumulative achievements that I get so that a list of obtainable achievements after loading a level will be documented.