The worst game I've actually played recently was.....Duke Nukem Forever.
I spent something like 19 hours on beating that game, no multiplayer or DLC. I had done a text-only LP (supplemented by an image of my facial expression as I played, as well as a quick video clip of me punching my screen while the game was up) on another site which was lost entirely when the site went down. It covered almost everything that occurs from beginning to end, a stream-of-consciousness quest.
It was....bad. Dull, slow paced, occasionally unreasonably difficult or unreasonably easy (with the spikes never corresponding to actual progress through the game; the final boss was as easy as the prologue), with bad humor and some downright offensive and even slightly disturbing bits, and hypocrisy at mocking other video games while shamelessly taking the tropes popularized by them to try and remain relevant.
The most aggravating part wasn't really the boredom, but that occasionally you could see something good. Like when Duke gets shrunk and adventures through a fast food restaurant at mouse-size, there's a long bit involving platforming in a flooded kitchen. There's extremely detailed textures on the items, even properly labeled shipping boxes with different items in each one (like paper hats). There's a kid's meal box that has a legible word search and maze on it. And it's all tacked onto an aggravating platformer with inconsistent physics that takes way longer than it should.
Frankly, I don't think it was deserving of being offered for full price on release. I wouldn't even pay $5 for a brand new copy now.