It's the same thing.
http://www.tasofro.net/touhou/index.html
東方萃夢想 is read as "touhou suimusou", and Immaterial and Missing Power is the English subtitle, which the English-speaking fans of the Touhou series use.
There's also a demo on the website if you're interested in seeing how the game works first-hand - click the download link on the page above and select the 110mb version. No Suika unless you buy the full version, though.