Okay, starting off the next 100 issues, we jump right back into Dell's comic strip reprint anthology and an Alley Oop creature feature!
This is bradysaurus, an early pre-dinosaur giant reptile big enough to warrant 8+1 HD, using d8 Hit Dice.
edaphosaurus was smaller, much lighter, and would only be 4 HD.
There is always a chance for wrecking things, even for non-Superheroes. So, Dan would get through even a steel door with an axe eventually, but it does make sense that he could forego this for time considerations (it might take many turns for the Editor's rolls to get lucky enough!).
Lastly, the trap of a false floorboard flooding the room with poison gas if stepped on is quite nasty. Of course, the Heroes still get saving throws vs. poison, and something less lethal, like knock-out gas, could be substituted. The chance of stepping on the right floorboard might be 1 in 6 per turn spent in the room, per occupant.
It's unclear in the bottom tier if we are seeing the benefit of a Charisma modifier being applied to an initially low encounter reaction roll, or if the Editor is applying a situational modifier after some good role-playing.
Landing on the railroad car could have been a simple attack roll -- unless the Editor wanted to make it really challenging and added the penalties for hitting a moving object, from the vehicular combat rules.
The man Easy meets in the snow could be the result of a wandering encounter check, but since he has such a valuable plot hook for Easy, I suspect he was pre-planted in that location -- which is okay for the Editor to do. Not everything needs to be random.
Easy slipped on the ice because of a missed save vs. science roll.