So upon hitting the "play" button in the launcher, before the game loads but after the launcher closes, suddenly the launcher pops up again, without a "Minecraft has encountered an error and needs to close" message.
By changing the settings to keep the launcher open, the game simply never launches. When I press "play", it looks like it's loading and then just stops.
It did give a log in the development console tab, though:
http://pastebin.com/upmxp5LU
I have not installed any mods, just the Forge - Recommended file for 1.7.10. I already searched the forums for "return to launcher" and found nothing.