If you have to ask such a question, you're in for a very bumpy ride. Game programming is a very hard task and even though you might have some game in mind to aim for, you'll fail to reach that goal.
All in all, yes SFML can be used for 2D and 3D stuff. The posted link is more 3D than 2 or 2.5D. SFML itself offers only funtionalities for 2D drawing, but you can use OpenGL directly, so anything that OpenGL can, "SFML can".