Let's try for some clarification - good idea to challenge me on that
First of all, with every case of overplay the next player only plays until the 2000 mark, i. e. less than 2000 turns effectively. This is indeed vital for easy tracking in my book. It isn't unfair to the overplayer - he overplayed due to his own carelessness - and certainly not to his successor. To the rest of the league? Not really - both players have played 4000 turns in total if both players survive, which is the normal situation. If either of the players died it doesn't matter how many turns it took for them.
I don't think there's a need to clarify that minor overplays won't be punished. I should probably point out that the game should be passed on at the earliest possible turn once the 2000 mark has been reached - if overplay happens because an action that went over several turns was taken then that's fine. Anyway there won't be repercussions if someone overplayed involuntarily. I doubt we'll see 50 turns overplay, much less in significant amounts.
Overplay and longer and shorter turns only become an issue in relation to the "always descend one level" rule. Simply enough, players cannot overplay in order to reach the next level. If you aren't one level lower after 2000 turns, you fail. I think that one is clear.
To ensure total fairness, it must also be made clear that the player whose turn is technically shortened because of the "play until the next 2k mark" instruction still has 2000 turns to descend one level. In other words, as long as he hasn't descended as demanded he doesn't need to stop at the 2k mark, but is allowed to play the full 2000 turns or until he has descended.
So in other words, if you overplay 20 turns, you still must have spent at least 20 of those turns on the new level. And your successor only has to play 1980 turns, but has the full 2000 to go to the next level (where he must stop at the 2k mark - not that he'll complain).
As I said, only malicious or extremely negligent - as in, significantly unfair to the other players negligent - overplay would be punished.
As to competitive and non-competitive play... Of course it's a Grey area, Grey invented the rule . There's a difference between bad strategy and competitive playing. We don't demand that players use the best strategy possible; everyone can certainly play as they are used to. With the Abyss rule in place the whole competitive/non-competitive thing becomes less important anyway; there's only a limited amount of competitive tactics that are mean enough to help, but not mean enough to risk one's being cast to the Abyss. What we don't allow is deliberate bad play for competitive reasons, and we don't have a mind probe at our disposal, as much as that would be a toy I'd like to try out myself.
Moving down that quickly is not the best strategy (arguably it's a pretty horrid one). But we have to allow for a scope of freedom for the players. They should play to the best of their abilities, but everyone makes mistakes or follows unsound strategies (some less often than others of course), and they should be able to do everything they decide to do in order to survive. And we can never account for the things that happen. It might well be that a player has to climb down ten levels in one turnset because while he was planning to descend maybe four levels, he had to flee from really dangerous shit starting from the fourth and ended up there by accident. I don't know all the circumstances in your example. It's going to be very hard to prove or properly find indication that he descended that fast with competitive intent.
The second case is more problematic. I'd have to take a look at the character to judge it properly. If the player in question had lots of other stuff he could've thrown away instead or could've eaten the rations with little trouble, that's negative points (and there's lots of stuff I'd throw away before the large rations have to go...). If he really does rely a lot on speed because he runs and shoots people all the time and needs the distance inbetween, I'm more inclined to believe it, especially if the character in question has many other kinds of food handy. Another case anything but clear-cut...
Certainly if there were protest from other members of the league I'd investigate both of these cases.
There are so many playstyles around that it will be very hard to pin any of this down. Thankfully the early periods of the competition will be less tense, and in the later ones where the major decisions are made will be under chaotic influence anyway...
I don't like unclearly defined rules either, believe me.