I think the lighter one looks better....at least on my screen

We can't pick for you since monitors will never render color correctly. If you can't decide find a friend with good color sense to help you.

Lighter, more variegated.

I like the one on the left but I must say we had the color on the right and it performed wonderfully with kids and dogs for almost a decade. But it was a very dense low pile nylon.

For a basement playroom I would not do wall to wall carpet. I would look into carpets squares. The FLOR tiles mentioned above. Easy to lay, stain resistant and you can replace any area that gets damaged or stained. We looked into them for our family room before deciding to go with hard flooring throughout the house.

Neither one looks good on my Mac.

Your title says playroom. Your pictures show a bar area? It does matter.

Is this a playroom for children? I understand wanting it to look nice, but I personally would go for the least expensive option for a child's playroom with a plan to replace it in the future. Does your flooring store carry carpet remnants? In our previous home we found a very large, dark blue remnant that was used for the children's playroom. The cost was minimal and it didn't bother us too much when it had to be replaced a few years later. The room did have 3 windows as it was a walkout basement so the dark blue worked for us.

Cars, riding toys, balls, and trains don’t like carpet. A rug is baby-friendly but not older kid unfriendly.