Okay I know this one is late and all but I enjoy this critiquing thing and figured I'd weigh in if you don't mind.
I'm gonna be brutally honest here, not a big fan of this particular key blade. I get it's probably meant more as a gag, since it's a plunger and all, but it's kind of on the basic side.
It's essentially just a plunger with a ring, key chain and a star attached to it. I mean, I'm guessing the plunger was probably the main requirement but you could have probably gone a little more creative with the design of the plunger.
Maybe make the shaft out of metal with some gems along it, with the tip being polished glass or porcelain or crystal, something to mix it up a bit. Least that way it offers something more unique in terms of appearance and visual flare is what I'm saying.
Then again if this is how the person who commissioned it intended for it to look I suppose that's okay, but if not, I'm just saying you should feel a little free to go a little crazy or give some more variety to it, atleast within reason.
I don't know, maybe I'm being too nitpicky here, and if so I apologize for that, just giving my thoughts.
Otherwise art is still solid enough, just the design itself is what bugs me.