Games should be fun. Rocketman is not fun.
As I said "Rocketman: Axis of Evil" is a top down shooter, but unlike "Ikari Warriors" it is a dual stick shooter. My experience with dual stick shooters is mostly with games like "Geometry Wars" or "Super Stardust HD", games where you are faced with unbelievable odds yet through the users maneuvering, targeting and powerups, coupled with the speed of the ship those odds were more approachable. "Rocketman: Axis of Evil" still has you facing unbelievable odds but the rest of the gameplay mechanics of a twin stick shooter are tragically missing.
That's not to say that the game does not have power ups because it does, and a good selection of them as well. Sadly though the power-ups are so powerful that the game goes from being insanely difficult to being a cake walk. This is all balanced out by putting a timer on the power-ups unfortunately the timer is so short that you end up over-extending your position in an effort to kill as many enemies with your powered up weapon. This will often result in cheap deaths from enemies off screen once your weapon has powered down. I am sure there are some players who have mastered the game that will tell me that there is a fine strategy involved in weapon use and map progression but I don't have time to master a mediocre game and honestly I don't care.
Unlike most dual stick shooters I have played, "Rocketman: Axis of Evil" has a detailed, if not entirely well-told story to give your slaughter of little green men purpose. The story is told through a series of anime cutscenes. I don't want to speak ill of the story but I stopped caring around level 3 and started skipping through the scenes, considering that I generally love stories in games that isn't exactly a glowing endorsement.
There was one piece of the game I enjoyed though and that was the character customization mode. By killing enemies you pick up differently shaped gold pendants and earn experience points which all works as currency in the game that can be spent at the end of each level to upgrade your character in a variety of ways. Be it armor, personal statistics, weapon stats or even stock for your arsenal of gadgets, "Rocketman" lets you upgrade your character anyway you want. Sadly upgrading your character has no real discernible effect on your in game character's appearance but I do so love to spend points on stuff.
Truthfully if you are looking for a dual stick shooter that is based off of an obscure constructable strategy game, then "Rocketman: Axis of Evil" may very well be for you. However if you are just looking for a dual stick shooter, I recommend "Geometry Wars" on the 360 and "Super Stardust HD" on the PS3, they are both far better games than "Rocketman" ever even had hopes of being.