The reason its in steams hand now and they removed the timer on steam is because the devs failed to meet the submit deadline on Friday before the weekend. Steam doesn't release small title games after a certain time on Friday or throughout the weekend bc they don't want to have to come in and work if something goes wrong. So the game wont be playable until Monday.
Most Steam games are released at 10AM PST, as Sbr mentioned, which is 19:00 in continental Europe and 6PM in the UK. It's not a hard rule as Steam sometimes does release games at midnight, but those are usually exceptions only made for "big name" games.Feb 11, 2012