That's why I'm saying that there was room for people to feint around if they'd cared to do so.
This really isn't true, I'd have to say in the Martians' defense. Or, insofar as there's always room, always, for anyone to "feint around" that was still possible, but there was nothing like the chance in most other recent games where a scum could claim an actual role/character and have other people legimitately believe he's that character. You'd have to assume the Martians knew all the roles of all the Innocents, and *then* were able to choose unpicked roles. Having 4 out of like 25 roles unclaimed does very little- now, sure a couple mistakes like claiming the character of an already dead Innocent could have been avoided.
But even if the Martians did nothing like that wrong, and just tried to claim minor characters from the movie, there was still way too high a chance they'd overlap with another random Innocent, and die from that. They had no chance of good cover roles unless they got really creative (and the Innocents got stupid, in all likelihood) If there were just some random "Innocent civilians" in the game and fewer roles from the movies directly in the game they might have had some chance, but as it stands not really on the cover roles.
Now, I again wouldn't say the Martians were underpowered with their huge numbers and number of kills (it is ironic that like the two recent games here with 6, 7 member Mafia teams led to some of the most resounding Innocent Victories). But the cover roles were nonexistant in all fairness.
(Of course, this could have been realized by the Martians and planned for, addressed by trying to prevent the Innocents from organizing and mass role reveal in the first place, or there's always the chance of just claiming the same role as an Innocent and trying to get the Innocent lynched first just to buy time/waste a day. So I would again agree the Martians weren't underpowered or couldn't do anything about it - but they had nothing close to easy cover roles from the average Mafia game.)