@Guillaume I would also much have preferred the GBC version, but it's an import and with today's release, chances are we'll never get it. God damn, the colours are so vibrant on the GBC version. *grumble*
I got Balloon Kid and it's fun! I don't know how long it is, but I made it to the end of stage 4. Definitely recommended if you like Balloon Fight. The game has quite a few nods to the NES original. The controls are an upgrade, the music is good (especially the end-stage music, just wow). The gameplay is simple but fun. You can let go of your balloons and do some platforming here and there. Then, you can blow up more balloons and fly again. Simple but fun stuff.