I just spent over an hour trying to beat level 5 of The End then after finally finishing it the replay glitched out at .02 seconds.  Luckily I could still hit a to get to the next level but I was really looking forward to seeing the hundreds of Meat Boys die and maybe even saving the replay. 
 
Just wondering, have you guys had replays that won't show, and were they all ones with tons of Meat Boys in them?

I'm not sure what kind of limit they have for attempts on a stage. I imagine it has to be a hard number like 20 or 50 or something. Maybe higher. A few stages I died a million times on, I forgot to save the replay. So, I'm not sure.
 
I've never had a replay glitch on me though, but it doesn't surprise me.

I had one replay glitch out on me today, where I did a cheesy strategy involving a specific character's ability to rewind time on one of the Salt Factory dark world levels. Other than that I've never had any replay glitches (other than having stuck, falling meatboys at the bottom of the screen).

But there does seem to be a limit on the number of meatboys in a replay. Not sure whether it depends on the complexity and length of the level, or if it's a fixed number, but it's easy to see in the later levels where you die a million times. The early attempts where you're jumping all over the place, getting killed in awkward places and such, are nowhere to be seen. Instead, the replay starts off with a huge chunk of meat jumping in perfect unison until hitting a bottleneck and becoming a bloody mess with just one meatboy making the cut. :)

Yeah Omega is a bitch.  I saved my replay though, if that makes you feel any better.  The mass of meat wasn't as impressive as I thought.

200 deaths and 187 mn completion (Damn Bandages on hard levels) still works, although every looks like a red line

There is in fact, a hard limit to it.  Sad but true.