Hi, looks like you didn't add any objects - you need to do this in the World's constructor. There's a tutorial here: http://greenfoot.org/greenroom/images/1/12/Adding_objects.pdf

Todom, my comment was on the "Pipes" scenario. There's a link to it from the "latest activity" box. qnanqing's comment is on that scenario too.

There's a big delay when you choose a level if you play on the gallery. The reason is you have the waypoint image set to "WayPoint_small.png" but the actual filename is "wayPoint_small.png" (i.e. starts with 'w' not 'W'). Filenames in jar files are case sensitive!! To fix it, you can change the image to something else, then change it back.

Ah, the classic "milk and cookies stuck behind the portcullis" conundrum :) I like this - simple, but nicely done. Love the hand-drawn artwork too, it gives it a comic-book feel.