The game itself is pretty short, but who doesn't love a quick upgrade game? That very first death came as something of a surprise (as I'm sure it does to most folks), but that's all the time it takes to catch on. Just upgrade, upgrade, upgrade! Then find a weapon and upgrade that, too. The graphics and animations work well in this cartoon style, which all felt very appropriate for the title. The music was pretty cool, too. My one and only issue is that I played through the entire game, start to finish, and never earned a single medal. Ah, well...so it goes. You might want to check that out for future players.
Also, to anyone who thinks that this game is nigh unbeatable, think again. After learning the pattern of the end boss, it's not actually that difficult to avoid every single shot. Then again, maybe that's easier for someone who's played a lot of Bullet Hell shooters. Anyway, I completely disagree that the upgrades are insufficient for beating the boss. There's a really easy way to shave a lot of time off the clock, for one thing. And by using the jump and shoot technique when the boss tries to crush you, it should be quite possible to take him out in three waves.