Are corrupted projects recoverable?

I was working on RPG Maker MV today as normal, when I went to play test. I used function + F4 to enlarge the screen after selecting new game, and my computer froze on the black screen. I was unable to alt-tab or call up task manager. The crash might have been something to do with my computer - but my RPG Maker MV project will not open. Instead, I get the message: "Unable to read file Game.rpgproject."

I have a backup about a week ago, but my work this week was particularly prolific and I will bet set back massively if I'm not able to recover anything in this project file. I never wanted to be on the end of one of these stories, and I suppose it's my fault for not backing up soon enough. Ironically, I was going to do that today.

So please, could anyone let me know if anything is recoverable? I'm rather heart broken at the moment.

So the .rpgproject file just opens the editor, it doesn't actually contain the hard work of your game. You can replace a faulty .rpgproject file with one from a new project.
What's worse is if your actual data gets corrupted. By that, I mean everything in the "data" folder of the project ---> database settings, map events, etc.

If you replace your .rpgproject file with a fresh one, try a playtest to see if it can load all of the data/resources. If a data file gets corrupted, it's likely only one file (rather than all of them).

Wow... so far so good.

Thanks @Aloe Guvner!

How much do I have to playtest before I know eveyrthing's fine? What have I actually lost by replacing the project file with an older one?

You don't lose anything by replacing the .rpgproject file. The ".rpgproject" file is just the launcher for the RPG Maker MV program (also called the editor). All of your project data is stored in the subfolders such as "data", "img", "audio", etc.

As far as how much to playtest to be sure... well there isn't a correct answer there. Try a few battles, check any maps that you recently created, go through a few weapon animations, you should notice if something is wrong.

Oh my goodness, I'm saved. Thank you so much for pointing out the project file remedy! Phew.