Higher-Order Fun is a game programmer's blog on 2D platformer implementation, math for game development, and programming essays.
HN commenters repeatedly link its guide to implementing 2D platformers as a nice, useful reference.
he also seems to have a nice article on 2d platformers: http://higherorderfun.com/blog/2012/05/20/the-guide-to-implementing-2d-platformers/
marked for reading.
I'm not the OP, but here you go: http://higherorderfun.com/blog/2012/05/20/the-guide-to-implementing-2d-platformers/
It looks quite nice.
I think this could help you: http://higherorderfun.com/blog/2012/05/20/the-guide-to-implementing-2d-platformers/