You can get a screenshot by pressing the "PRTSC" button on the keyboard and pasting into mspaint.
The image you posted was actually from one of my projects and the cap is in this topic:
There isn't a direct counterpart of custom attributes in C2 although I think you could do something equivalent with families, Boolean instance variables and some more events. Although I would opt for a different approach.
For the example of an attribute like "left" you could do something like the following:
1. Make a family and call it "left_attr" and add any objects that could get that attribute to it.
2. Add a boolean instance variable to the family and call it "left".
3. Then in events or the editor you can give the objects the left attribute by setting "left" to true. Also to reproduce and event like "sprite overlaps left" you would do the following:
left_attr: Is left
sprite overlapps left_attr
Oddly enough after I answered your question about growing grass I made a capx to experiment with similar water physics. It's not perfect but it does work better than the CC version. Have a look if you like but be warned I used some math trickery to reduce the number of events.
Left click to draw walls, right to erase.