some people have not had time to build the Trample Steam which is located at the second build table in Die Rise most people will come across. On solo play, I have created a video of how to build it by only opening two doors and being able to collect all the parts for it by around round 3, so it is not too difficult to do.
Its a great invention that help catapult zombies out of your way, or if there is another building you want to jump too but cannot make it with the normal jump, this catapult will hurl you across at great speed. It only takes a few seconds to set when you put it down. One problem with it is that the zombies will attack it, but you can pick up as many as you like from the table if it gets broke and every player in the game can have one each.
Be careful not to place one trap on one side of a jump and another person places a trap where you are going to land on the other. Once you flip across, as the other tries to fire you back, its not as strong sometimes and causes you to fall to your death. Definitely squeeky bum scenario time.
Here is a curious zombie wishing he had never been born examining the Trample Steam: