6. Call Of Duty: Zombies
With a franchise getting as much time, attention and more importantly MONEY pumped into it each and every year, it's quite surprising when rogue glitches and gameplay altering experiences make their way into Call of Duty. However, this specific bug was actually only discovered by people who went above and beyond when they dominated the Zombies mode.
This bug completely derails the experience if the player can survive past round 163 on the insanely popular game mode, which is no small feat, let me tell you!
After this point, the health of the zombies resets thanks to their data being tied to a 32-bit binary and can result in them instantly dying or being killed in just one shot. As you can imagine this somewhat affects the tense and frantic gameplay, as now enemies go down with next to no effort, yet it doesn't stop there.
As before mentioned this is a binary code, basically meaning there's an off value and an on value, and as such this glitch only happens every OTHER round, meaning you'll have a brutally hard wave and then a ridiculously easy one, and balancing both can throw players for a loop.
Weirdly enough this glitch appears in multiple Zombies modes, specifically the ones developed by Treyarch, possibly suggesting the team can't fix this without breaking something far more important in the mode.