The movie was well-made, but for some reason, it wasn't such a big hit with the public, which I thought was a pity.
こんにちは。
ご質問ありがとうございます。
"The movie was well-made,"=「映画は良く出来ていた」
"but for some reason,"=「でも何らかの理由で」
"it wasn't such a big hit with the public,"=「あまり世間的にはヒットしなかった」
"which I thought was a pity."=「それは私は残念だと思った。」
ご参考に。