You should definitely take a look at Struckd Studio which is now part of Unity Play - https://play.unity.com/en
It's still a little buggy in places, but nothing that can't be overcome.
You can drag and drop in 3D assets and many of them come with built in and easily changeable behaviors. Then there is a node based programming language that you can use to make alterations.
It's web based, but also has iOS and Android apps available for editing and playing the games.
edit - I'm an educator working in the CS ecosystem, and am playing with Struckd with the intention of making a suite of learning resources.
It's still a little buggy in places, but nothing that can't be overcome.
You can drag and drop in 3D assets and many of them come with built in and easily changeable behaviors. Then there is a node based programming language that you can use to make alterations.
It's web based, but also has iOS and Android apps available for editing and playing the games.
edit - I'm an educator working in the CS ecosystem, and am playing with Struckd with the intention of making a suite of learning resources.