Would love a save button, the random auto save function is not very visible and feels very random. Often i come back to the game and missing a lot of levels or starting in a different area than when i closed the game.

Playing on the steamclient.

just closed it as normal after reaching a new zone (after the animation finishes).
jumped back from 9,5k crusader levels to 4k and was back at zone 71 instead of 112

since the very beginning of this game, 272 days for me, 'save' has never ever occurred as you describe it when I close my browser tab or window.
I can prove it right now by using Storm Rider and if I close the browser within I guess 5 minutes as you say the max interval is, and then reopen it, the storm rider was not used, the game was in the state prior to the last actual save not any imaginary save that a closing of the game is supposed to do.
I even reported this as a trouble ticket on 1/15 and got this response:
"Hi Raymond,

Thanks for reporting!

In addition to saving during important events during gameplay, the game also forces a save when you close the tab/window. I just tested this, using magnify + storm rider and immediately closing the tab, and after opening the game again, the bonus was still applied.

My only thought is that you might have had some internet latency, causing the save call to lag, and by turning off/sleeping/hibernating your computer, you interrupted the save call.

I hope this helps. Let us know if you have any questions.

Sincerely,
Nick"


please note, I am not putting the computer into sleep mode or hibernation or screen saver, I AM closing a browser.