I think that is not acceptable to do things this way.
If HM decided to put some limitations to the level rush, I'm fine with it. The problem, is that you cannot be around not releasing information in case something gets bugged, so you are going to say "oh! it is intended that way," when the outputs seem counter intuitive.
This situation creates a state of frustration to the player, and just demoralizes and reduces the fun in the game.
I think that they need to clearly state what are the drawbacks of the level rush, so you can willingly do so, and not just waste them.
I try for two days several things to "discover" (as HM claims) the "fun" parts of the level rush, just to find out that I wasted my (now reduced) veteran/expert attempts.
Not cool. Not cool at all.
