Hi
Ok, not saying it's the easiest game to build, but really, this is all very simple from a technical point of view.
-- RageSpline is available on the asset store, so modifying the cube visually like it does on this game is likely very possible, and would only require a few custom actions
-- RageSpline is maintained with a set of PlayMaker Actions, and I think, it's now managed by Maddox, so I am sure that if you ask kindly, you'll get playmaker actions to modify shapes the way this game does.
-- as far as the actual physical behavior, this is a very simple drag and shoot concept.
1: click and drag, record the distance.
2: on release, add an force using the distance ( I would even dare trying the square distance for more spectrum) as a multiplier, and use the drag direction as the direction ( the opposite of it)
and done. so really, this is not a complex feature, nor a complex game at all. It's simply perfectly executed!
Without RageSpline, you would then have to modify the cube vertices themselves, which currently is not accessible within playmaker as standard, but I can provide with the necessary custom actions to do so. And Kiriri is right, MegaFier would indeed shine in this exercice with a 2x2x2 FFD box as the modifier.
The trick with stretching the cube and not the eyes is simple, and can be achieve in two ways at least:
-- the eyes is a different mesh... problem solved
-- the eyes uv is within a given set of faces, to that face is not actually made of 2 faces but 18 faces ( 9 squares, with the center one being the eyes). Think of it like the 9-scales images or image caps in IOS.
So, totally feasible, even with PlayMaker with a bit of work on custom Actions. Using third party plugins like RageSpline will be mandatory of course if you want the exact same visual look obviously.
Bye,
Jean