Ok I have put together a capx to show how you can fake 3d, with scale.
I hope this can be of help to anyone who is interested in this kind of effect.
If you find it too hard change the 'astermake' global variable to a bigger number.
For those who want to play it online go here sizzle-games.com/3d'ish
or scirra arcade
scirra.com/arcade/action-games/blast-3178
Arrow keys to move, spacebar to fire.