So I took the time to read the IGN review yesterday, and they really only devoted about half a page to the games flaws... the rest being a dramatic commentary about Sonic (particularly their love/hate experience with Unleashed) and praises of the presentation.
Based on what I read, the basic faults were:
* Waggle for attacking, not precision motion control
* Levels were more about hacking through hordes of enemies than any real platforming
* The bosses were stupidly easy
* The premise is an insult to the franchise
* Multiplayer is miserable
* Sonic is ridiculously slow
* Campaign is rather short
And the pros are:
* Terrific presentation values
* Decent voice acting (although crippled by horrible script)
* A large amount of fanservice
* Good music
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Also, several people are saying that IGN did not play as Sir Percy, Sir Lancelot, or Sir Gawain, but that is probably not true because there is a huge chunk of footage in the video review devoted to their gameplay.
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Now personally, I expected the waggle, as adding precision swordfighting would make it nearly impossible to implement effectively along with the mad speed Sonic needs, however if the levels are truly more hack-n-slash than roller coaster platforming, this probably is a legitimate concern.
Sonic being miserably slow could have to do with some kind of upgrade system like SatSR, but IGN doesn't seem satisfied with it even after they were done with it. However, I found the speed in SatSR bearable and reasonably expanded, but I'll need to get a few more opinions to find out what this means for Black-Knight.
As for the premise, being a medieval junkie, I hardly think that it will bother me. I have heard from several players that the game was legitimately good, but I probably should go through a few other critic sites to get a proper idea.
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In the end, IGN said that the game was "only for the truly radical most fanatical sonic fans, and if you are one of those, you've probably forgiven a whole bunch of other bad games, so why not add another one to your list"....
This does annoy me a bit as I'd rather know what kind of gameplay/genre appeal it has rather than how stupid I'd have to be to want it, but considering I liked Sonic Unleashed and Secret Rings, that probably means that very little there would really bother me as much.
Overall, I'll ignore IGN's rating, but its low enough that I have to make sure that I know why it got it. As it is though, I'll probably get this game when the price drops... just as I did with NiGHTS.