Ra can be really good on mars though thanks to his card that makes him immune to fire damage, which is always nice to have out when Fire in the Biosphere comes up, and doubly nice if you know FitB is coming.
That said, I agree mars is the hardest environment, I don’t know if it’s the least fun though. However, it’s probably the least fun if you’re playing Zero, Bunker, or Wraith as it’s just way too difficult for you. But Visionary doesn’t care about Red dust, (no equipment in her deck), and for Legacy, Ra, Tempest, Fanatic, Tachyon and Haka its only really a minor setback. As these characters either 1. dont have much equipmenet in their deck, 2. dont rely on their equipment all that much, or 3. both. Getting 1 equipment card back when its destroyed is A-OK for tachyon, Ra, and Legacy anyway, so its little more than a 1-turn annoyance for them. Haka often has so many cards it doesn’t matter, and if not he can always fall back on Crush instead of using his weapons. Tempest’s equipment isnt that necessary to his play (I like gene bound shackles, but I’m not gonna cry if I lose it, especially if I get it back right away).
Poor Bunker: Losing all his equipment means he can’t attack unless he plays another peice of equipment. Add to the fact that the only thing he’s got that’s NOT equipment (or 1 shot) is Ammo Drop and Modes. that doesn’t make for a hugely productive turn for our friend bunker, especially if you’ve been going for the Turret Mode/ Flak Cannon/ Grenade Launcher DOOM setup that is oh so effective with Bunker, it just doesnt work on Mars.
Poor Wraith: Like bunker she suffers from the “loosing all my equipment means I cant actually deal any damage” scenario. Fortunately Wraith can get her stuff back quickly if she has Impromptu invention. And then it will probably all get destroyed again. But she still suffers comparibly less than Bunker, IMO, so that I think she’s kinda playable on mars, but she certainly doesnt shine as much as usual. On a plus side, those grappling hooks turn out to be REALLY handy when dealing with those hard-to-reach base-self-destruct mechanisms.
Poor Zero: Hey! I can still do damage without any equipment! Unfortunately it would only be to himself. So that’s not very useful. He probably has it the worst when Red Dust comes up (I dunno, toss up between him and bunker…) , but if he’s got Isothermic Transducer and/or Coolant Blast in play, he’s actually really nice to have around when fire in the biosphere comes up. Still, it can take him several turns to get rolling again, which is just brutal for an already slow-to-start character to get hit with the reset button all the time.
All 3 of these characters do kinda okay against Voss on Mars, because Voss has no equip destruction of his own. Blade, Omnitron, and Dawn all have equipment destruction in their decks, so you effectively have to deal with a reset probably almost twice as often, which is super hard. Wraith is probably still viable. I’d not suggest Bunker or Zero if you had the option. Pick your characters smart, and Mars Base can be plenty of fun.