Questions on refinishing a table

[PeteSB75]

So, I picked up this table pretty cheap from some guy on craigslist. It's in pretty good shape, few dings, some marks, etc. Looks to be pine, no veneer, just stained/finished.

I wanted to make it look a bit nicer and use it as my kitchen table, so I sanded down the top with an orbital sander. Had to work a few spots a bit more than the rest of the table because of dings/marks/etc.

Once I put a coat of stain on it, those spots turned out darker than the rest, obviously I didn't remove enough of the previous finish/seal on the rest of the table.

So, my question is, what do I do now to make this table look ok? Do I need to use a stripper and take all the finish off the whole tabletop and stain again, or should I just sand it down again and throw another coat of stain on it or do I need to get a darker stain and use that?