Recs.
Updated
SpecsUpdate
Pros
Pro Powerful events system to create games without programming
No need for coding using this system which is clear and powerful: events are composed of conditions and actions. Actions are launched when conditions are fulfilled. This is a very friendly way of making games and is still efficient for advanced usage, contrary to most other "block"/"drag'n'drop" systems.
Pro Quickly add behaviors to objects
Prebuilt behaviors can be added to objects. This is a very efficient way to add a physics engine or make a platformer game. Lots of behaviors are included, from the most advanced (Physics, platformer, top-down movement) to really simple one (like the behavior to destroy objects when outside the screen or the one to drag objects with mouse or touch). And you still have full controls over your game as behaviors can be modified using the events!