I'm liking this game a whole lot. I know this might involve a lot of work, but it'd be GREAT if there were more multiplayer components (ie dynamic boss battles with X number of players). However, this is a great game nonetheless so far.
TO DEFEAT HARD MODE ANCIENT FEAR: Max out the Librarian's Cleansing Light, as this skills' damage is based on the enemy's CURRENT % HP. Open the fight with a heal, then barrage the Ancient Fear with Cleansing Light (as such, play this character first). Jake should have a max Tiger Shot and high Hitpoints and should be played second to maximize total damage. You can use Last Flake to tear apart the Fear with Rake, or build her as a tank with loads of HP and points into Bite and Regeneration in order to withstand the Fear for the longest amount of time. Angela should have a max Diamond Shot with Poisoned Bullets improved to give you a lucky edge (hopefully). Marco should be used as your last ditch, maxing Dodge and Headshot to keep enemy hits away from you. Of course, the more HP every character has before starting the fight, the better your chances of succeeding. + so that players having a hard time with this can see.
This game HAS to have a sequel! + if you agree. Goes without saying that this game is very addictive and has great potential. While having its educational elements, it also appeals to gamers using its real-time strategy/defense elements.