Sinistar is a cool concept, but it's just too hard, and it throws too much at you for it to be much fun to play.
So, you're like the spaceship from Asteroids. This evil space fleet is building this space weapon named Sinistar, which is like a floating fortress with a skull face that spews digitized taunts at you. In order to stop it, you have to mine Sinibombs by shooting apart certain kinds of asteroids, since your peasly laser beam won't even scratch the dreaded Sinistar. While you're mining, though, there's an endless supply of these little zippy red drones called Workers, that buzz around you and try to snatch up any Sinibombs you jar free before you can pick them up. What's worse, if they grab a Sinibomb, they'll take it and use it as a piece to build Sinistar. There's also the Fighters, of which one or two are usually near you somewhere, which are UFOs with rotating turrets that mine asteroids on their own for Sinistar parts, but will also come over and take potshots at you just to keep you on your toes.
Anyway, it generally takes about two minutes or so of playtime for Sinistar to be completely formed, which is when the lulz begin. Sinistar immediately starts cruising around at high speed, and eventually he decides to zero in on you. When he does, unless you're really lucky and get a big asteroid in between him and you, he'll just totally outrun you and kill you instantly by mushing you in his jaws. While he's doing this, radio personality John Doremus provides a great digitized voice (the first in gaming AFAIK that used actual recorded clips and not weird Stephen Hawking voice synthesis) that taunts you with catcalls of "RUN, COWARD!" and "I LIVE!" along with a really excellent beast roar when he either eats you or when you chip a piece off of him with a Sinibomb. Once he's completed it takes 13(!) Sinibombs to destroy him, but of course the miners and workers can repair him on the fly as well. Oh, and if you manage to kill him ... THEY BUILD ANOTHER ONE FOREVAR!!!!11!!1!
Basically, the odds are just too ridiculously stacked against you to even off one Sinistar, and it just seems depressing to be fighting these things forever. It's good for a game with this kind of ambiance to be hard, but it just goes over the line into complete impossibility unless you're willing to devote a year or two of daily practice to getting a Black Belt in Sinibomb mining or something. Chill out and have a Cinnabon instead, it'll stress you out much less.
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