What is a factory-blemished tool?

It is a RIDGID tool with a cosmetic flaw from manufacturing, sold at a lower tier than new stock. The tool itself is the standard model with the same motor and features.

Can the hammer drill bore into concrete?

Yes. Hammer mode plus 525 in.-lbs. of torque lets it drill small-diameter holes in masonry and brick. For repeated large holes, a dedicated rotary hammer is faster.

How deep will the circular saw cut?

The 6-1/2 in. blade gives a depth of cut around 2-1/4 in. at 90 degrees, less at a bevel. That covers 2x framing lumber but not thick posts in one pass.

Do both tools use the same battery?

Yes. Both run on RIDGID 18V batteries, and the kit includes a 2.0 Ah and a 4.0 Ah pack plus a charger. The 4.0 Ah is the better match for the saw.

Is this kit enough to start on the RIDGID 18V line?

It gives you a drill and a saw on the platform, and the batteries and charger work with other RIDGID 18V tools. You would add tools like an impact driver or recip saw separately.