FYI There are some known issues:
FIGHTS NOT ENDING: (partial fix: Press R on your keyboard - it will force the fight to end)
Rather minor case: Sometimes enemy spawned on right side of the board can be immortal
or
More severe case: one of your units disappeared after dying in fight. It is still counted towards max sloths on board, and fights don't end. - sadly this was a big oversight and there's nothing much to do at this point. You can still use the "R" method but the game is potentially broken after this issue occurs. To prevent the above from happening, whenever you see that your unit is MOVING or ATTACKING while fight isn't happening, try to move it around the board until it stops OR get it off board and sell it if it's not to valuable for you, this SHOULD prevent those issues from happening.
I'm sorry for those issues, hope the game will still be enjoyable dispite them.