I have participated in two cook-off’s only but 20 minutes penalty is way too much and someone having a minor bug who submits a minute later will be behind all those who submit after him in the span of those 20 minutes. In atcoder the penalty is 4 minutes which seems very reasonable, also at codeforces you lose 50 points which only affects the submission on problem A, and for rest of the problem -50 is ok. Codechef should definitely reduce the penalty to 10 minutes.
Heads up to that shifting to Saturday suggestion. Cannot wake up late on Sunday because of colleges and stuff the next day. For the 20 minute penalty, of course, even I feel that 20 min penalty for a 150 minute contest is harsh, but it depends on how much they want to stress on “AC-in-first-try” concept.
Well, it would be better if cook of is shifted to Saturday.
But i have different idea for time penalty. The idea is to reduce time penalty to 5 minutes with the adjustment that the user cannot submit another solution for same problem during this time. This idea is worth implementing if and only if it doesn’t cause much difficulty.
The best part of this would be that the flow of submission will be less, which would reduce the load on codechef servers, something that has been the trouble of last minute in codechef.
Another variation of this idea is to set a custom resubmit and/or penalty time for each problem which may be higher for easy/cakewalk problems like 10 min and less for medium/medium-hard problems or even 0 min for hardest problems.
This idea of differential resubmit time would strongly stress upon AC solution for atleast the easiest problems. Another benefit is that users are going to carefully analyse their solution before submitting.