My guess is that they are not affiliated with Scirra, because they would've mentioned it. Also, Scirra has the pick of the litter and probably would have contacted devs directly and not through a forum.
$150 isn't much unless you can finish the game in an hour or two. C2 does make the job easier, so maybe they feel the labor isn't worth as much.
In any case, if you are new, have a lot of free time on your hands, and don't have any paid work experience, something like this might be worth considering. Sometimes the best way to break into a tough industry is to volunteer your time in exchange for experience and networking opportunities.
Just don't do jobs like these forever. If you don't value yourself, no one will.