First showing concepts before talking lrizes is already a bit shady to me. You can run of with those ideas any time.
How is that shady? Try pitching anything without having something to show for it and it'll be a very short, very pointless conversation.
"Hi I have a game for you."
"Ok cool what is it?"
"Well it's a ball and it jumps across a level and you collect stars"
"Nice can I check it out?"
"No! I wanted to talk first! How much will you pay me for this game you know nothing about except me talking about it?"
EDIT: That said, getting paid $25 for a unique game mechanic is horrendous, don't ever take deals like that, you're messing up the perceived value of games for everyone.