In most games you can find one form of a glitch or another. Sometimes these can be very minor and not effect gameplay at all. Other times they can cause the game to be un-winnable or un-playable. It is for this reason that it is very important to test the design of your game for glitches that could prove to be disastrous.
Examples[]
Sphinx and the cursed Mummy – There is a major glitch in Sphinx and the cursed Mummy that if triggered will make it impossible to complete the game. At one point there is a single door that you need to go through to progress to the next section of the game. However, if you save the game at the saving station right outside the door then load your game from that point the door is closed with no way to open it.
Example #2 Superman 64
One famous example of a game that suffers from countless glitches is Superman 64. Some of the many glitches include failed collision detections, game freezes, etc. A classic glitch from this game lies on the game’s start screen. It begins with Superman flying around and collecting rings to show the player what to expect. Superman after a minute or two proceeds to fly into a wall and get stuck. This game received universally abysmal critic reviews.
Example:
The another example for games which has glitches and ruined the gameplay is "Red dead redemption". Red Dead redemption is an open world western action-adventure video game published by Rockstar games. The glitch in the game is Wagon flying here and there and the horses appear in sky. This glitch distracts the player from gameplay.