When comparing HaxePunk vs uScript + Unity3D, the Slant community recommends HaxePunk for most people. In the question“What are the best 2D game engines?” HaxePunk is ranked 22nd while uScript + Unity3D is ranked 97th. The most important reason people chose HaxePunk is:
Useful for mobile games and soon consoles (OpenFL has a console port in the works).
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Joystick and multi-touch support
Useful for mobile games and soon consoles (OpenFL has a console port in the works).

Pro Crossplatform testing/releasing
HaxePunk uses OpenFL which means you can compile to just about every device. A lot of the rendering code has been optimized so if you use HaxePunk’s graphic classes you are pretty much ready to deploy on any target.
Pro Generic entity system
A generic Entity system that only uses what you “attach” to it. If you need collision masks they are available but if an entity doesn’t need to collide with anything then simply don’t add a mask. Same goes for graphics.
Pro Written in Haxe instead of AS3
This comes with blazing fast compile times, proper static typing, multiple output targets, and a powerful macro system.
Pro Multiple collision masks
HaxePunk has added several collision masks beyond what FlashPunk had including a grid with slope values, circles, and polygons. This is in addition to FlashPunk’s tile grid and hitbox.
Pro Tweens
Tweens are available just like they are in FlashPunk. If you need to interpolate values for sounds, movement, etc… it’s probably already available as a tween. There is also a VarTween that lets you interpolate any value you want.

Pro Automatically generates nodes for third-party script assets
uScript's nodes are a visual representation of actual code blocks, and it takes advantage of C#'s reflection capabilities to automatically create nodes for any scripts it finds in your project, regardless of the source. This makes it inherently compatible with pretty much everything.
Custom nodes can also be created by hand, for cases where the automatically created ones contain more elements than they actually need.

Pro Versatile flow diagram script model
Modeled after UDK's Kismet (the predecessor to UE4's Blueprint), uScript's scripts resemble flowcharts where each box represents a function or value, with connections between them representing program flow. This provides a better at-a-glance indication of game logic than a simple list of events, and makes complex behaviors easier to accomplish.

Pro Generates C# source code
Nodes are translated directly to C# files in your project. This is great for learning to code, and also for advanced users who can use uScript for fast prototyping and then further optimize the scripts if necessary.
Cons
Con Messy / fragmented documentation
Not a lot of documentation is available.

Con Small comunity
It’s a small but growing community.

Con Not that easy to use
It's a lot more complicated compared to something like Playmaker. Same tasks take a lot more time.
