How do you unlock mountains? Forest is area 500 on island. I thought mountains would be area 1000 on forest but it didn't unlock.

I found that this takes a very long time (months) with many rebirths. I had to try to get to level 50 K, 30 K, 25 K, 10 K on the lower levels to get to 4500 on the top level. I used a lot of potions (all the time). After a certain point I focused only on damage from archers, lasers and missiles. I ignored clicking, and bombardments. I reached 4500 (and got placed 26th on the leader board - not sure if there is a reliable ranking for those at 4500) when I had about 2.2 M "Health" and about 8500 for my "...

Since the game has zero instructions beyond the basic upgrading, does anyone have a strategy worked out? IE is it generally faster cash to stay at a lower level w 2x monster speed and mini boss monsters? It's what I've been doing on my current run (2nd rebirth), but I have no idea. Seems like being able to jump around on the map / go backward would be helpful to experiment with....

is there a way to have the mega boss's auto start when they become available if you've killed them that run? Is there any 'auto click' item or gem bought thing ?

This is a question for the dev, and maybe my shop just doesn't work :(