I watched this movie on Hulu.
I had heard good things about this film for years, but never got around to watching it. I didn't really know what it was about till I started listening to the SinCast (the podcast for CinemanSins), and them talking about it.
so I gave it a watch, and I loved it!
A very cleaver spoof of horror movies and their tropes, while also celebrating them at the same time and actually being a good horror/slasher film on it's own right. And it did it without feeling at all like Scream. It's funny, it's subversive, and very well written. I've heard some people don't like the ending, and sure there are a couple issues with it, but I loved how it ended. Felt like the perfect ending.
To give a summery of this movie would ruin some of the surprise, and I would advice going into this movie blind.
Mistake Status: N/A.
★★★★★
Quantom X ★
Answer: It's stated that the tunnel should have blown hours ago, so the initial failure is most likely human error, that the order to blow the tunnel simply didn't get through to the demolition team on schedule. The subsequent problem blowing it up is referred to as being related to "a glitch up top", later stated as a "power re-route upstairs". While not stated outright, the only plausible explanation is that this was, as you rightly stated, due to Marty messing around with the equipment that he found in the hatch.
Tailkinker ★