Originally Posted by Diverjoel285
So I beat the game on hard and noticed I missed one collectible. I level select and find my missing collectible and finish that level but not achievement. I kept the difficulty on hard.... do I have to beat the last level again??
I think you might have to play the game from the beginning to end. I managed to get that Achievement by getting all the collectibles and upgrades on my previous playthrough on Easy then upon my next playthrough switched the difficulty to Hard and played it from beginning to end.