When Toys R Us closed its doors, customers mourned the loss of a beloved brand that conjured memories of their own childhood. Retailers, on the other hand, saw an opportunity.

Rather than cede any more ground to online behemoth Amazon, companies like Target, Walmart and Party City ramped up their offerings. Now, ahead of the pivotal holiday season, they're going even further by focusing on making their stores a dynamic shopping experience.

That means creating play areas for kids, offering demos of new toys and staging events like scavenger hunts in the stores. Retailers are trying to grab a piece of the nearly $3 billion left on the table by Toys R Us, or 12 percent of the U.S. toy market, according to NPD Group Inc., a market research group. Last month, Party City opened 50 Toy City pop-up shops that feature six-by-eight-foot Lego dinosaurs and other interactive displays. Walmart says 30 percent of its holiday toy assortment will be new. It will also offer 40 percent more toys on Walmart.com from a year ago. In November and December, the company's toy area will be rebranded as "America's Best Toy Shop."

Starting in late October, Target will devote extra space at 500 stores located near former Toys R Us stores for bigger toys like electric cars, playhouses and musical instruments as well as adding nearly 200 more products. And 100 Target stores will see new layouts and fixtures in the toy area.

The company is also expanding the number of kids' events it hosts. Most recently, it had a Lego Minecraft event that featured a scavenger hunt.