For those upset about losing troops, the game doesn't save during gameplay. This means just reload the page. Your last save will be after the last completed mission prior to the one you were on and all your losses (and gains) from the the one you were on will not have happened as far as the game is concerned.
You don't lose xp when you die, but you will have to start over from the last checkpoint. This can be used to re-play parts of the game and get extra xp, especially from bosses. You get xp from landing attacks, so you don't have to kill the boss, just hurt him as much as you can without killing him then let yourself die. Keep on till you have as much xp as you want.
I had a bug where I could go through all terrains when I was collecting the crystals with the air lady. It was when you have to run through the burning flowers.
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