I opted to purchase this game on GOG because I wanted to support the developer. (pre ordered i)

Now the game is one of the best I have ever played no question, but why is cheaper to buy it on steam than on GOG? I feel a bit cheated by my choice of platform. I would expect it to be more expensive on steam due to steam taking a cut? I feel a bit cheated, that's all. The difference is not big, approx 1 £ but still.

Edit:

OMG, since I had USD set on my profile I ended up paying 20.5 £ instead of 19.99£

I've got both at $49.99 on Steam and GOG. They're both on sale for $24.99 right now too. Got to be careful about which currency you're paying in :D