My concrete is surrounded by a retaining wall so there is nowhere to put it in the ground without going through concrete, is that possible? Or would I be better off with the portable goal?

If your concrete is strong enough you can use an epoxy wedge anchor to bolt down the basketball system instead. If it's not strong enough, you'll need to jackhammer through and pour a footer for the basketball system. Lastly, yes, you can go portable but remember, the base of a portable takes up a lot of space so unless your have a lot of space I think I'd look at trying to get the in-ground system to work. Hope that helps. Please give us a call to discuss if you'd like 888-600-8545.