I honestly haven?t played an objectively bad game. But I can think of some well-regarded games that are fundamentally broken in some ways.
Far Cry - Enemies that see you from miles away through foliage and buildings. Easy is more difficult than the hardest difficulty in most shooters. A final arena-type level that throws tens of enemies at you that you have to cheese to get through. Stealth is non-existent and shouldn?t even be mentioned as an option.
Uncharted Drake?s Fortune - Odious jet ski sections. Platforming/puzzle sections that give you no idea as to where to go. People laugh at the brightly colored platformable ledges/pipes/etc. in Uncharted 2, but you really see why they?re needed after Uncharted 1. The pop-up to shoot in cover makes you an easy target. It just doesn?t work, especially on higher difficulties. However, standing behind cover and corner shooting makes it impossible for enemies to get a shot on you.
Mass Effect - As much as I love the world building and story in this game, it is such a great example of bad design in so many ways. The inventory system obfuscates what weapons you have and how to use them. The compartmentalization of armor, weapons and mods for each one of them and all of your squad members is such a hassle that you?d rather ignore it. The combat is janky, the assault rifle?s reticle covers the entire screen until you find an accurate one late in the game. Too many biotics for each character, each with their own cool down, and it always comes down to spamming all of them at the start of each encounter.
And then the moral system that ruins the choice in dialogue. You don?t choose dialogue based on what you would do, but how best to fill a fucking bar with blue or red. And paragon/renegade doesn?t even net you anything.
Resistance 2 - I think this might actually be a bad game. I can?t even remember anything about it.
Metal Gear Solid 4 - Where do you even start with this beast? You know what, I won?t.
Red Dead Redemption - This one feels wrong to put on here, regardless. Mission design becomes repetitive and the story isn?t good enough to keep me engaged. The world and atmosphere are fantastic, but damn if I wasn?t over the typical Rockstar mission structuring. It really isn?t a good game from a gameplay perspective. If a sequel ever arises, I?d love a more intimate tale where your choices affect the towns and people around you.
Gears of War 2 - After the fantastically structured/paced first game, this one has some horrible on-rails sections and is all over the place with setting. Also, really bad last boss.
Doom 2 - I think Doom 1 is the perfect package. Doom 2 is too big for its bridges. Really weird level design and gross aesthetic. Higher difficulties throw way too many enemies in and you?ll always run out of ammo.
Bioshock 2 - Look, the story?s limp but I don?t care about that. From a design perspective, this game is outstanding. Except for difficulty. Hard should be easy, and the abundance of ammo/supplies destroys your will to explore and scavenge.