Also, I can't select the 'Brilliant Overload' skin despite having unlocked it, and the Skins can only be selected when you hover the mouse cursor over the the title of the skin, instead of the full line :o
Other than that, while I've discovered the amount of Gold you carry does accumulate after each game (as in, you got X amount of gold in one playthrough, died, start over, get more gold, die, and you have more gold to spend :) ), it does not increase beyond 4 (maybe due to no more gold being spawned to collect etc?), making it next to impossible to acquire the Pointless Book :/
Edit: Never mind, I managed to accumulate enough Gold in order to purchase the Grimoire, which gave some insight as to what to do to get that last achievement, and also, clever use of the names Thomas and Jefferson (& that reference to 'Lord of the Flies', which I kept forgetting about XD)