Justin and I have zillions of ideas for powerups and enemies, and there are also plenty of suggestions from other people. A couple more have already been planned and coded for updates, and there are a few more game modes in design/development (@ajdef3, will look into/consider a more casual mode of play), it's just that you can't simply "add" more monsters or powerups, they have to be carefully weighed and balanced in order to fit into the game right. If I put in a powerup that is too cheap, it trumps out any previous strategy and just weaken's the gaming experience. Or alternately, if we make it just useless and/or too common of a powerup, it would reduce how often each individual powerup shows up, giving luck and probabilities too much value over game skill (something which is already hanging in a fine balance in Skullpogo).
So ideas for monsters/powerups are welcome, but I can't guarantee that every idea will just be plopped on the game
What I can suggest, though, is that more gameplay modes be suggested or added, because those can be added without damaging the integrity of the current ones.
I'm pretty sure an/the TouchArcade editor is already aware of the game's existence and has played it (he was on the score list according to Justin a couple days ago). It's up to them at this point to decide whether the game is publishable or not. We'll see!
Thanks for the feedback guys, hope everybody whose purchased it so far is enjoying the hell out of it!
By the way, if anybody is also a forum-goer at TouchArcade, feel free to drop by the Skullpogo thread there http://forums.toucharcade.com/showthread.php?t=30331