I swear by these tracks. They are fantastic for stamina, punching strength, timing, and kick strength. I received some tracks dubbed with music (pantera, weezer, chemical brothers, techno). Bad ass. Build slowly, but eventually you'll be able to do all the rounds in succession.
May I ask which "2 minute rounds" track? He has boxing, thai boxin, and MMA sets. If it is either the TB or MMA, you should think about throwing a knee or a kick at the end of each combo. Preferably, you can throw a knee when shadowboxing and kicks when working with thai pads or a bag.
You should use the search engine. You'll probably find a wealth of info about this.
Good luck and train hard.
And remember the liver shot is a low left hook/uppercut hybrid (opponent's right side).