There are several different endings in Bioshock 2 for the PS3, Xbox 360, and PC, and there are also several different ways to achieve them.
Here is the list of alternate endings in Bioshock 2, and how to see them.
Good Endings
Method 1: Save all Little Sisters you adopt, and spare Gilbert Alexander, Grace Holloway, or Stanley Poole
Method 2: Save all Little Sisters you adopt, and kill Gilbert Alexander, Grace Holloway, and Stanley Poole
Normal Endings
Method 1: Save at least one Little Sister, and harvest at least one Little Sister, then choose to die at the end, and spare Gilbert Alexander, Grace Holloway, and Stanley Poole
Method 2: Save at least one Little Sister, and harvest at least one Little Sister, then choose to die at the end, and kill Gilbert Alexander, Grace Holloway, and Stanley Poole
Bad Endings
Method 1: Save at least one Little Sister, and harvest at least one Little Sister, and choose to live at the end and spare Gilbert Alexander, Grace Holloway, and Stanley Poole
Method 2: Harvest all Little Sisters you adopt, and spare Gilbert Alexander, Grace Holloway, and Stanley Poole
Method 3: Save at least one Little Sister, and harvest at least one Little Sister, and choose to live at the end and kill Gilbert Alexander, Grace Holloway, and Stanley Poole
Method 4: Harvest all Little Sisters you adopt, and kill Gilbert Alexander, Grace Holloway, and Stanley Poole
