This post may contain minor spoilers.
Super Meat Boy 125% progress (legit 100% completion). Deaths: 10945
So it turns out this game is super glitchy in terms of tracking progress. Sometimes the game won't save the levels you beat and the bandages you get, and you have no way of knowing when it stopped saving until you turn the game on next time and see all the levels that got erased. This happened to me a lot. But the completion percentages and bandage tracking remain the same. So when I replayed levels and re-got the bandages, the percentages kept climbing. I ended up with 25/20 bandages and 149% complete in one of the chapters.
I didn't realize this was a glitch until very recently. I thought the game was just really awesome and allowed you to complete over one hundred percent of the chapters, and there were actually 25 bandages available in each chapter instead of 20, and the counter was just out of 20 to fool you. I spent a lot of time looking for the last bandages in the worlds that said 22/20 or 23/20. I also got excited because I thought the achievement for 100% completion would activate when the game progress on the statistics screen said 100% and not when you actually beat every level and get every bandage. I realized it was actually a glitch when I only counted 20 bandages on the screen.
I made my last post when my progress on the stats screen said 100%. My Light World progress was over 100%, and my dark world was somewhere around 60%. I knew I would post again when I had actually completed 100% of the game, as I have now. As Lizard Dude pointed out, though, I didn't have the 100% achievement. I thought that was because I actually did need to get legit 100% completion, but weirdly, the achievement unlocked only a few levels after my post. Before I got the Beat the Dark Worlds achievement. So the achievements are glitchy too.
I don't know if my deaths were erased along with the levels during the save fails, or if the death count kept climbing like the percentage. I would say I had about a thousand deaths in my replay attempts. Among many smaller one- or two-level replayings, erased at some point were: the entirety of Cotton Alley light world, the entirety of The End dark world, and a few Warp Zone bandages and other tough bandages.
So I pretty much got cheated out of the best part of this game: the glorious feeling of beating a level and the satisfaction in knowing I will never have to do it again, because I did have to do it again. And it wasn't the same the second time, because I knew I'd already done it. In short, this game caused various amounts and various varieties of RAGE.
But it's a fantastic game. Great atmosphere, great characters, great music, great control and gameplay feel. And it's hard, but it's not super hard. Once you figure out how to play it, it's actually pretty easy. It just comes down to how fast your muscles can memorize the feel of each jump in the level. Yes, I was angry when I had to replay a bunch of levels, but it didn't take long because I'd done them before, I knew the trick and where to go for each level. I could probably play through it again right now and beat it in under 2000 deaths. But the trick is to do it immediately, before my muscles lose the memory. I'm not going to do it though, I just kicked this game's ass and it can go suck one.