His constant attempts to assure everyone how smart of a guy he is only serve to make him look like more of a dumbass. Smart people generally don't need to tell everyone how smart they are.
Additionally, just because you made some games on Unity3D it doesn't mean you're a developer. I spent 300+ hours making maps and minigames in CS:Source but that doesn't make me a developer. You don't even have to call yourself a gamer if you don't want. Just don't mislead people. Once again, the guise of "Developer" only serves to make yourself look better (which it fails at) and to inflate your ego.
You can't multitask. It's called being unskilled at Halo. You can't graphical design. It's called not being creative. And that's okay. Just own it.
Please for the love of Bane cut this the fuck out. All of what I've mentioned above is why people dislike you. If you stopped acting like you're above everyone else and started treating people like equals or with respect, maybe people would soften up to you a bit. But no. You remain as pretentious as ever.
This isn't meant to insult. This is meant as a wake-up call for you. Realize these flaws within yourself and work to fix them. Stop striving to bring others down when you could be working to raise yourself up.
Or to just stop being bad at Halo.