First 5 minutes into the game, I was hooked
Never have I thought that a shooting game could be this much fun. I like this game so much that I have both Japanese and American version of the game. There isn't much difference except the Japanese version is quite a bit harder because there isn't any health guage for enemy bosses.
Other reviews that says this gameis too easy and has only 4 hours or so of playing time is very misleading. The difference between Easy & Hard mode is huge. Even a toddler could finish the easy mode of this game in a day, however, the hard mode is considerably mode difficult. On 'Hard', most bosses will make you try at least 20 times to advance to the next level.
Even though, on hard mode, it takes forever to beat a level sometimes, it's the perfectly excuted control system that minimizes the aggravation. It's such a joy to control Astro Boy in this game.
I found the controls on other games to be quite awkward and limiting, but to my delight, Treasure implemented a perfect control system and crammed as many moves as could on the very limiting GBA controls.
If there's one caveat I can point out, it's the occasional slow-downs on some boss levels.
Even if you don't particularly like shooter games, I recommend trying at least this one. At such a bargain price at around $15-20, you simply can't lose.
Now, as a new fan of Treasure games, I'm off to playing Gunstar Super Heroes! :)