Thanks —
Just for interest's sake, it's being made using the stock Physics plugin. So far, so good (thanks to Ruskul for helping me out with a quick code amendment to allow me to add kinematic bodies, should the need arise).
The reception on Steam Greenlight Concepts and FB indie devs has been rather cold (and a tad hostile from some) because of the game's appearance. It seems that any game using physics puzzles and silhouettes will instantly be compared (with 'clone' accusations abounding) to Limbo... I'm having a good think about whether or not to invest the next few months of my time trying to make this work as a full-up game, or just put it down to learning.... The snag is that using silhouettes allows me to get away with much more simple graphics than I would otherwise have to use; even the animated character is full of limb-position crimes that you can't see because it's all black. I also like the visual appearance the silhouette gives... Meh...