Just going out on a limb here, but the ps1 crash collection, with the exception of crash bash.
Crash 1- Controls were a bit hard to master, combine that with over the top levels, and you have a hard, unfair game.
Crash 2- Most likely just me here, but late game gave out aku mask's and extra lives less often than early levels.
Crash 3- Some levels felt easier than others, I'm looking at you, level 25.
CTR- Some platinum relics require you to be absolutely perfect, which means a mistake equals a retry.
I also felt like the game was a bit short compared to the other titles, though I should be giving this to CNK.