Power Strike (known as Aleste in Japan) is a difficult game to find, at least in the US. A quick search on eBay revealed no copies available on eBay at this time. I manage to pick up a copy at the Video Game Summit earlier this year and I almost didn’t buy it because I didn’t know if it was an official US copy or not due to the monochrome insert surrounding the case. As such, it turned out to be the real thing as the monochrome insert was a cost saving measure by Sega late in the Master System. Also, I believe the US version may have only been available through mail order, though I can find the evidence to back that up at the moment. At any rate, it’s a fun title that is definitely worth picking up if you can find it for a good price.
Power Strike for the Master System was developed by Compile and published by Sega in 1988.