The amount of work you put into it, unfortunately, shouldn't dictate how much you sell it for. Rather, how much you work should result in how good the product is, and depending on the market/how many markets you sell it in, how good it is should result in how many sales you get (plus marketing/etc).
It's really difficult to judge the price you should place the game at. And ultimately, I think that the reviews you receive in an early version should give you a better idea of how much people will be willing to spend.
But for a more concrete answer, I'd say sell it no more than 4.99. If it does well, make an expansion (or sequel), and make more money. These are just my feelings; and to be clear, I feel like 4.99 is a max, not necessarily a recommended retail value.
But finally, that is a generic answer. If you have it on one market where games can sell well for $10, go for it. But if you have it available cross-platform, with a potential audience in the hundreds of millions, I say go with a lower price.
LASTLY, there are books and online resources that have done research regarding game sales and pricing. Might be better off looking there.
Or just wing it and hope for the best.
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p.s. 3.99 is a little less common. could be a winner. idk.
Anyways the game looks great, and the scirra arcade version is a nice intro. Congratulations on your sponsorship!