Ah, what a good idea is, to add the cannon on the top, make sure it is redstone powered (make sure you change the distance of the tnt travelling- you made need to expand the cannon slightly). Make sure it looks simular to the cannon you uploaded in the attachment.
I don't really download someone else's skin. I make my own, and just upload some to planetminecraft. I always have really used my own skins. To improve: You could include more detail, like sometimes when I make a skin, I always include slight shading example: I place a pocket in, I include slight shading, so if it was a blue pocket, it would have darker blue surrounding it. I have recently uploaded my latest project. Check it out and see what you think of my work.
I have minecraft since beginning of BETA. I learnt all there is to know in a week (in the survival aspect). I then realized all the mods that could support you. I know most redstone gateways etc... I have made 2/5 of my adventure map progress (Bacon Legends). I have made tons of rollar coasters.
Coal is to common, I am starting to think minecraft is just too easy now, I mean even diamond is easy to find now. :/ I hope 1.8 makes the game more challenging.
Creepy indeed. It is about time they implemented a challenging mob, I mean common, creepers are very easy, zombies are very easy, the only slightly challenging mob has to be the skeleton.