Casino Nights DLC adds a pinball machine in Sonic Generations. It is not a level. The name sounds misleading, Sega should have named it Pinball DLC, but whatever.
The machine itself fits into a single screen. You see a glowing blue Sonic as the ball. You pull the plunger to launch Sonic and you use the left and right flippers. It feels like a simple machine, like it could be a real machine in an arcade. It uses a version of the Sonic 2 Casino Nights music.
There are a few frills. There is an area with two bumpers. If you get the ball into the area and bounce it around enough, an elevator will appear. Once you're up the elevator, it is a series of catwalks to roll around on. There is nothing special up there.
This is all for points, just like a traditional pinball machine. The game keeps track of your score and the high score, but that's about it. This is pretty bare bones, but if you like pinball in your Sonic games, this is for you! Otherwise there are other pinball games out there with a lot of variety and more features.
With the DLC installed, you can find the pinball table in the hub level after you complete the first two levels of the game.
There is nothing wrong with it and it would have been a great extra in Sonic Generations without it being DLC. In fact more games should have a pinball table in them. It just feels like this is a lesser pinball table than actual pinball games offer. Sega could have a pinball game with tables inspired by all their old games much like they have Sonic and All-Stars Racing. That's probably over analyzing a pinball table for less than $2 that needs another game to run it.