Alright here is the problem: the creators of a quite popular flash-based game have asked me to port their game to Android. They are not interested in any other platforms so we don't need to be worrying about iOS or PC. They want the best performance on just Android (I guess that's the point of porting a flash-based game. They could have just went with it)

They found Unity 'slow'. How would the performance (on android) of other engines compare? Are they expecting too much i.e. finding Unity slow? I am in favor of Unity since development is a little easier with more things being visual (I am not experienced as you might have guessed).

This would be an example of the type of game I am to port

Thanks!