TCP is kind of the full feature kid on the block. You might do better making up a protocol that has what you want and skip on the rest. There are real latency costs for parts of TCP that a game will never use i.e. Nagle's algorithm(sure you can turn that one off but every thing has its cost and you can't turn off everything you don't need in TCP).

I am surprised how infrequently RTP comes up in these conversations. Something close to RTP seems like it would be ideal for games.