Apply a concrete resurfacer, it's available at most home improvement stores. They apply easily with a squeegee, and the cost is minimal. They even now offer a restoritive coating made by some prominent paint companies. Your choice, hope this gives you some ideas. ;)
You could grind it all down, stain or paint the entire floor then seal it. Or lay outdoor tiles over it. I watched This Old House the other day and they were redoing an old deck by laying 2'x4' wood 'tiles' over the old decking. When done it looked like wood planks but the 'tiles' just snapped together. You can also get ceramic tiles that look like wood.
You can apply restorative coating on the affected areas, which you can get at your local paint stores. This method is both easy and effective if you do it on your own, though you might require some professional help.