X Construction Lite is one of those games that will leave you incredibly frustrated, but at the same time keep you coming back for more punishment. In some ways, X Construction Lite is similar to World of Goo, in that you have to build structures (usually triangle based for strength) to cross canyons. In X Construction Lite the purpose of this is to get a train of passengers safely across your bridge. Fail to build your bridge strong enough and your bridge will collapse, complete with screaming passengers,
Don't go thinking this is a simple game. I am still stuck on level 7 of the lite version of this game, after trying to build my way across two expansive canyons using what feels like far to small a supply of girders. I am sure there is a simple solution, but at the moment it hasn't clicked. That's part of the beauty of X Construction Lite. Because it is difficult the sense of accomplishment when you succeed is far greater than your average 300+ level physics based android game.
All in all, X Construction Lite is a great game, which I thoroughly reccommend.
In the words of the of the developer:
Build a bridge to let the train safely cross the valley.