To burn the spider you can use Wall of Fire, but not the positioning is really important but the moment you do it. Use it as soon as the spider apears because it bounces a bit and reaches close to the ground where the fire lies
I have completed all 30 missions, bought the PowerMode (unlimited durability and fuel) and then landed on Mars. Yet the Mars Reached will not get checked on the hard achievement list. Any ideas ?
 "A knots story"){kind=icon}
 "Decision 3"){kind=icon}
 "Sentry Knight 2"){kind=icon}
 "Dillo Hills 2"){kind=icon}
 "Into Space 2"){kind=icon}