The DD's house, soon to be on the market, has a large game room about 20x20 with dark stained concrete floor. They did this themselves, and throughout the process were very aware that they didn't know what they were doing. They are not sure if they sealed it.

Consequently (we assume) there are two large swaths that look like a scuff where the color is much lighter or perhaps even down to the concrete.

The local man who does these floors says it would be expensive to sand off and re-do.

He said it is possible to clean the floor really well and try to darken the stain in that area, then seal with wax. But he also cautioned that more than likely it would not look any better than it would just cleaned and waxed if the areas we stained were then darker than the rest of the floor. These scuffs are pretty noticeable, in a traffic area.

So...if we were trying to darken the stain in those areas, what would we use and where would we get it?

If we were sealing the floor/waxing it, what would we use, plain old paste wax?

Other advice?