The PSP version of Fieldrunners is, surprisingly, a significantly enhanced version from the one I picked up when I had an iPhone; there are five maps instead of three, and the presentation feels slightly snazzier than when I last played it eight months ago; the explosions are a little brighter, maybe? It costs a few dollars more, but I think it's worth it; having tried a few other tower defense games since then (PixelJunk, Ninja Town, and Desktop), none of them have really scratched the itch quite like this one does.
Yeah, I got all the achievements except one because at a certain point in the game, the little errands just stopped showing up at all.
I farmed a few achievements, but became frustrated when I realized the GREEN THUMB achievement for picking 30 flowers from gardens was unattainable for me, because I had the audacity to complete Art 5 (which meant I no longer had to give people gifts in order to kiss them), leaving me with an inventory full of flowers I couldn't even throw away.