As others have said, this horizontal shoot-'em-up is rather difficult - especially in the later stages. Playing this game with a partner does help through most of the game, but we found that the last stage was easier for one player than for two, because of all of the running-into-the-wall deaths which sucked up all of your shared continues. That said, with the 9 credit code and/or the 'level select' code, this game become much more playable. I rated this as a '9' out of 10, because I REALLY enjoy simultaneous multi-player games.
For those interested, the 'cheats are as follows:
Extra Credits - At the title screen press Right, Right, Right, Select. The word "Credit5" should appear beneath "Blaster Scramble 2" then push up or down to select from 0-9 credits
Sound Test - Activate the Extra Credits code, then press Select at the title screen to access a sound test menu.
Level Select - Activate the Extra Credits code, then press Button I 10 times to start at level 2. To start at higher levels, Press button I once more for each level above 2. (i.e., 11 times to start on level 3, 12 times for level 4, etc.) To complete the code, press Select, Select, Run for 1-player or Select, Select, Select, Run for 2-player.
Hard game but very fun, underrated in my opinion. There are some other "hard" shooters I have not beat because they don't keep my interest long enough, this however did.