I'm not quite happy with it enough to put it in the store, as I said there are a few issues with GG that mean it doesn't work quite as well as I'd like and there are a few areas I would like to polish a bit.
When Lee gets back of holiday I'll email him about the, um, strange behaviour I've discovered (can't really call them all bugs yet as Lee may have a very good reason why they are there) and take it from there.
In the mean time a few teasers, entities can be picked up, rotated, and dropped. If you place an entity on top of another that is level (i.e. not rotated in x or z planes) in such a way that it won't topple off then it is 'stacked', this means that if you pick up the entity it is stacked on then they both move as one.
Any number of entities can be stacked and carried, I'd really like some way of reading the physics characteristics from within Lua and controlling the movement speed of the player based on the total 'weight' of the objects but that is probably a long way off.
Been there, done that, got all the T-Shirts!