I got it for around 100+ (incl shipping) from a guy in England at ebay, quite a while ago. I missed several guys who were selling their copies at their website for cheap price. Is it worth the price? Personally, of course not. It is a solid game, but no where near what it's going for now. Then again, so are most of the Neo Geo cart games in general. So, if you like NGCP, though, why not get it (but $150 is too expensive).
It's rare beacuse of availability--I think 10,000 copies of UK copy exists VS 4-5000 copies for Evolution. But I think Faselei! costs more, because it is a better game. And that number is now smaller, because SNK of Jap recalled the UK games. They supposedly rewrote the Roms and sold it in the Jap market
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"Come on, get serious!"