So get this. You're in a rocketship with a limited supply of air and fuel and you need to rescue stranded astronauts and then get the hell out of there. Your rocketship is not so much "ship" and mostly "rocket" - or sort of like a potato with a roman candle shoved in it, so maneuvering around space is NOT what might expect. You're fate really depends on how well/poorly you employ the gravity of nearby planets, without actually letting the planet pull you to your fiery death.
Blast Off is a simple well-polished game and I commend the developers for having a vision, seeing it through, and making it look tight. The sounds are fitting and professional, the graphics are simple-but-fun, and the gravitational pull mechanic will either be the perfect challenge or drive you loco. (si mami) Either way it's a pretty neat effect though.
See, it's tough to give a C score to a game that I got hooked on for a good while. Getting used to the gravitational pull of the planets was quite tough, but I did get better and better so I believe that I was hooked on the learning aspect. Some people will really enjoy honing their skills around this mechanic, while others will probably quickly tire, and wonder why they didn't get to blow anything up. I spent so much time hopelessly trying to get back on screen (because I flung myself so far offscreen) that I can imagine many people will hit the 'wtf!' wall and call it a day.
My issue with the 'hone your skills' aspect is that there is really no mechanism built in that can help you actively measure the success of your attempts. The thrust level and angle of blast off are not recorded or measurable, so when you start over, you're prone to make a different mistake rather than tweak your performance and then make incremental progress. For me personally, I would have loved some form of measurement, so that I truly gained knowledge after every blast off. I think some playtesting would have revealed the need for slightly more ship control as well, as to cut down on the aforementioned frustration of blasting way off screen (not fun) or immediately getting pulled in to a planet (death). Of course there's really no punishment and the game encourages a quick restart of any level if you so choose.
There's a good amount of levels to try and while I didn't get too far in to them I can imagine that they get pretty damn tricky from what I experienced early on. (start on 'easy' folks) This game isn't for me personally (at 400 MP) although if I could see myself killing time with it at work if it were on my PC, more than at home. As mentioned, I believe that this fits a certain type of gamer who enjoys the addiction to conquering a challenging mechanic. If that sounds like you, don't stop get it get it.