I generally like programming games like this, and it reminds me a lot of lightbot which is a good thing. I agree with other comments on minor things that could be improved: either give a clearer explanation about how to use the keys instead of mouse to enter commands (especially about the fact that you have to press space to select a track before any keys work, even if there's only one track), or make it so the first track is automatically selected to receive keyboard commands. I'm also not a fan of the kids cheering sound at the end of the levels.

More importantly, this seems like a nice game engine, but it really needs more difficult levels. Maybe looking back at other games like lightbot could help spark ideas on how to make more challenging levels. Or if you changed the mechanics slightly so that bulldozers can push other bulldozers around instead of having the level stop if they collide, maybe that could allow you to design more challenging levels where people need to use that mechanic.

become fun @ level 18....
( so 15 levels not fun for begin !)

i dont understand why it is UNDER JUDGMENT . i lke it

Simple, but brainbreakingly INGENIOUS! I congratulate you on your brain skills to make these puzzles, must have been even harder to think of em then it is to solve em hee hee.If possible i'd frontpage you right out from submission area XD

Would like an option to just double click the arrows to add them to the queue, dragging them over every time is fiddly and unnecessary. There are keyboard shortcuts but they need better explanation; it took me a while to figure out I needed to press space to select a track even when there was only one available. It would be great to be able to go to the next level by keyboard as well. Also the children cheering is really annoying to hear repeatedly as well. The game itself is decent. Took until level 20 to get difficult; would recommend separating levels by difficulty.