What happens if you try to Time Travel (adjust your clock/calendar) backwards? (Cozy Grove)

Motivation for this article

The game can behave badly in a variety of ways if it thinks that the date-time has gone backwards. In some cases, a player's save file can end up in an unrecoverable bad state and the player has to delete their save and start over.

In order to help protect players against accidentally ending up in this situation, version 4.2.0 introduced a protection against backwards time travel. However, the way this protection works has occasionally confused players. This article is an attempt to explain how the protection works in hopes of reducing the confusion.

Two possible approaches to the problem

Identifying that the date-time has gone backwards is easy for the game to do. But after this situation is detected, what should we do? We considered two approaches:

• Pop up a message saying: "STOP! You cannot play until you roll your clock & calendar forward to at least this date-time." And prevent the player from doing anything until they comply.
• Instead, always let the player play but have the game adjust the game's clock and calendar to a compliant date-time.

We chose the second approach, which isn't as straightforward but has the advantage of never preventing a player from playing. The rest of this article details how the game works in light of this choice.

The general idea

Whenever the game detects you playing on a date-time (per your device's calendar and clock) prior to a date-time you've already played on (as recorded in your save file), it uses the device's time (just the time, not the date) as the game time then rolls the game date forward the minimum amount (possibly zero days) needed to maintain a "date-time never goes backward" state.

• Note that the game has no concept of the "real date-time." It only knows what date-time the device says it is, which you (as the device owner) can adjust to be either in sync with reality or different from reality.
• Likewise, the date-times written to the save file are based on whatever date-time the game is using when the save is written. Which, for a backward time traveler, might have been neither what the device said nor in sync with reality.

The upshot of this is that the game always pushes the date-time forward (because the game can behave badly if the date-time ever goes backwards), but sometimes it will still be the same date, and other times you will be pushed forward to the next date, regardless of how many hours or days you have adjusted the device's clock/calendar by. Which of these happens depends on the device time (but not the date) now relative to the device time (but not the date) of your last saved play session.

• This is admittedly a little weird, but consider that the right answer isn't to never push you forward to a new date (you'd be stuck on the same game day forever!). And if we were to always push the date forward by 1, you'd only get one play session per game day which doesn't work if you want to spend multiple play sessions in a single game day (e.g., so you can collect some shells now, then come back a few hours later to collect more). So this is our approach for determining when to sometimes advance the date.

Nuances

• If your device date-time is less than 36 hours in the past when compared to the most date-time most recently written to your save, then none of the above happens. This is to ensure normal behavior for a player who isn't trying to Time Travel but physically travels across time zones, which could legitimately change the time by as much as 24 hours if crossing the International Dateline. (We went with 36 hours rather than 24 just to be safe.)
• The described behavior assumes that the time doesn't jump around within the same play session. It's not feasible for the game to be constantly checking for weird calendar/clock behavior, so it checks at some sensible points that will hopefully cover most accidental situations. (As we've mentioned elsewhere, the safe way to intentionally Time Travel is that you should only travel forward, never backward.) I'm sure that if you're actively trying to break the game, you can bypass some checks and get into some bad situations, but the point of this feature is to prevent losing months of progress due to an accidental backward Time Travel, not to plug every possible hole in Time Travel.
  • Suspending a play session (most common with Switch and iOS players) is in some sense still the same play session, so you should be extra careful about jumping around in time. I recommend exiting from the main menu after your final play session of each real day, as well as whenever you know you'll be time traveling in another game (e.g., Animal Crossing), to minimize the possibility of accidentally goofing up Cozy Grove's timeline.

This is confusing!

Yes, it is. We'd prefer that you either don't time travel at all, or that you are always very careful to ensure that each fake date-time on which you use the game is always later than the last fake date-time on which you used the game. (But sometimes accidents happen even to careful players.)

Can I keep playing in this confusing state?

You can, and the game should work fine. Just keep in mind all the things mentioned above regarding how the game's date-time is going to advance while you're in this state.

Can I get out of this confusing state?

Yes! You can do so by fully exiting the game (don't just suspend it!), rolling your device's clock and calendar to be AFTER the max date-time your save has ever seen, and then starting the game and loading into your save again. (If you aren't sure what that max date-time is, you can check on either the Save Slots menu or at the top of the Progress Debug Screen.) Since the game will now think that you're not playing in the past, it won't behave as described in this article. But whenever the game thinks you're playing in the past again, you'll be back in the confusing state covered by this article, so you'll have to remember to adjust your device's clock and calendar before each play session.

I recommend doing one of the following if you have trouble remembering how much to adjust your clock and calendar by:

• If not playing for a few days will let reality catch up to your save's max date-time, consider doing that and then not Time Traveling anymore. Always being in sync with reality is less mental effort than constantly figuring out how to manipulate your clock and calendar before every play session.
• If you'd have to wait longer than a few days for reality to catch up to your save's max date-time, consider instead rolling the calendar forward to be exactly 1 year (or 2 or 3) ahead of the real date whenever playing Cozy Grove. Remembering only which year you need to set the calendar to before each play session is a lot easier than remembering a year, month, and day.