Difficulty was somewhat overrated after a few tries. As the tricks to each level of Gauntlet are assimilated, it's relatively easy to do a full run. Harder to do without death/detection but far from impossible.
The best tip I can give: If you have to wall-jump over traps in between walls, don't jump at the wall first - instead, try climbing it from the ground, that will build more momentum (this helps a lot on gauntlet level 2).
Another tip: Any shift key works, so you can do a two hander for a much better control wih WASD and right shift.. Try in.
To unlock every last medal/achiev, do the following:
- Do gauntlet fast (I got speed run with a time of 4:04 and some deaths)
- Do gauntlet with 9 or less deaths (Don't know if inclusive, try to die 8 times max)
- Do gauntlet without any death (Not even once)
- Do gauntlet without being noticed by "detector" traps (Use shift to navigate the mazes and NEVER pass any laser/gun/rocket and probably shock balls while visible). And probably don't die either.
It's hard but not entirely impossible. Remember, you don't need any haste to do any of that except the speedrun one.