Thanks for the feedback!
Darkening unelectable paths would most definitely help, maybe also brightening up your options of where to go could help visually communicate the linearity of the map.
Enemy genration is a bit off. There is a difficulty stat that directly affects the generation, but it is not always spot on and there is still some variance. The only thing that really is controlled for the most part is the total health and mass of the enemy island. I'm working to fix this problem specifically and the changes will probably be dropped in the next update. It's probably going to be a massive rework of the enemy generation system to work with some new mechanics I'm sticking in, like having limited weapons for instance.
Anyways, thanks for your feedback to help make this game better and more appealing!