Code:
 on *:text:!shootwater:#:{
  if !%esplay && !%seadra {
    notice $chan This game is currently for %esnick only!
  }
  else {
    inc $+(%,water,.,$nick)
    if !$timer($nick) {
      $+(.timer,$nick) 1 25 shootwater $nick $chan
    }
  }
}
alias shootwater {
  .msg $2 $1 $iif($($+(%,water,.,$1),2) > 9,good job!  You killed Snorlax!  Inside of him was a special Chansey egg Use !openegg to open it.,lose!  You win nothing.)
  unset $+(%,water,.,$1)
}

For some reason, and I'm not sure why, the 3rd parameter wasn't being passed to the alias properly. The above code works around that problem and has been tested.