Nuclear Throne

The goal here is to beat the nuclear throne in under 10 minutes. Personally I didn't risk looping or anything so just kill the boss when you get to the throne to be safe. Now getting a speed run going, it is crucial to do the skip in level 1-1. This requires you to damage no enemies and open both chests and the radiation canister. This will spawn the 1-3 boss, which you need to kill quickly. This will bypass worlds 1 and 2 and put you into an underwater level. Clear this and you will be spit out at the 3-3 boss fight. From here all that's left is to hope you get good weapons and mutations that you like. As long as you perform the skip and get a decent run it shouldn't be too difficult to beat the throne in under 10 minutes from here, just keep trying if you get bad runs or fail.