In agreement. Martyrs had been hyped to hell but just gets stupid at the end which doesn't live up to the first couple acts.
Frontiers was really good.
Those french fellows certainly love putting their leading actresses through it!
Also agree with you and Ravenholm: Both films are quitre good, although I also found that Martrys faulters a bit in the last half as well. And just as such like you both, I find it quite a shame. But allin all, still a fine above-average genre film well worth owning, flaws and all.