That was disappointing, actually. It had looked good. Admittedly I'd put off watching it for years because the TV version had such ludicrous censorship. (All the gore was being blacked out in this extremely violent anime, making it almost unwatchable.) However the uncensored Blu-rays are fine, so I've now watched those.
One-line review: it's like Starship Troopers (good) until it turns into alien superhero battles (boring) with too many flashbacks (not relevant).
The title's clever. It could be read as "Terror Formers" (because of scary monsters), "Terraformers" (because Mars got terraformed five centuries ago) or "Terra for Mars" (i.e. going from Earth to Mars). All of those are valid. It's the year 2620 and there's a worldwide epidemic of a Martian virus. It's 100% fatal and we can't cure it. The only thing we can do is send people to Mars to take biological samples. Unfortunately this mission will encounter one or two teensy-weensy challenges:
(a) everyone going to Mars must undergo surgery to be given animal characteristics. Barely a third of these subjects get off the operating table alive.
(b) Mars has cockroaches. These arrived five hundred years ago, when mankind originally terraformed the planet. These have now evolved into a highly organised super-strong humanoid species that will show up in an army and try to kill you.
(c) whatever you're imagining, you're already underestimating the cockroaches. Admittedly they look silly, but they're cleverer than you think and they'll act before you're expecting them to. (Personally I quite like the roach design, with those flat black eyes that make them impossible to anthropomorphise.)
The first few episodes are good. Someone wasn't trying very hard when they looked for names (e.g. the German's called Adolf), but the space travel is realistic and the violence is impressive. Don't mess with a cockroach. You'll get your head torn off. Anyone can die and at this stage the show's looking like a decently hard-hitting SF survivalist terror epic. There are even pyramids on Mars, which gave me a Doctor Who buzz. The uniforms make everyone look like Rurouni Kenshin's Aoshi, though.
After lots of fun bloodshed, though, we discover that the humans have heroes! Remember all that surgery? That gave everyone superpowers, so you might have super-strength and explosive spit like a blast ant, the ability to spin threads like a silkworm, etc. It's Hornet-Man vs. Cockroach-Alien-Man! The cockroaches stop being scary and mostly just become cannon fodder for the superheroes. The show then becomes mostly about these superpowered fight scenes, plus lots and lots of flashbacks to people's former lives on Earth.
That's it, really. The show stops moving forwards from about ep.4 onwards. Fight fight fight. The cockroaches themselves are quite interesting, admittedly, since they keep surprising you with their intelligence and their ability to do things you weren't expecting. There's also the question of what happened to previous expeditions. Basically, though, it's pretty flat.
The OVAs put a worthwhile wrinkle on this, mind you, by jumping back twenty years to the last Earth expedition to Mars (Bugs 2). This is an entertaining premise because we know who's going to die (i.e. almost everyone). I also liked how the OVAs opened, with a nice girl telling her friend not to fight the cockroach that's walking towards them. Show no hostility. If you're willing to talk, your feelings will definitely come across. Uhhhh, no. Personally I'd say that the OVAs are better than the TV series, because it's a shorter series and because the backstory flashbacks are more horrible. The superhero fight scene thing still applies, but it's less boring here because you know almost everyone's wormfood.
This isn't a bad show. You've just got to accept it for what it is, which was a problem for me because I'd been enjoying the Starship Troopers bloodbath. I'm not expecting to find anything interesting in the 2016 sequel series, but in fairness the sequel has a different director, studio and production team. I'll watch the first episode and see what I think, anyway. I'll also definitely be watching the Takashi Miike live-action film, despite not having had good experiences with Miike's recent manga adaptations. (Even I'm not planning to watch his JoJo's Bizarre Adventure.) With this 2014 series, though... it's just nothing special, really. It's space soldiers and aliens. It's not really doing anything you haven't seen done better elsewhere. However it's not incompetent and I'd cheerfully recommend it to anyone who was looking to scratch that particular B-movie itch. It's violent. It has Martian cockroaches that can cut you in half with a kick. Just don't expect the show to be noteworthy, or even particularly good.