To accept this offer, you must first cancel the auction to remove your asset from the auction contract.Keep this tab open. Once complete, you will be able to click "Accept Offer" again to execute the transaction.
The CryptoPunks are 24x24 pixel art images, generated algorithmically. Most are punky-looking guys and girls, but there are a few rarer types mixed in: Apes, Zombies and even the odd Alien. Every punk has their own profile page that shows their attributes as well as their ownership/for-sale status (here's an example).