Last boss on hard is really a bitch, got it down to about 1/3 of his health and he instantly kills off Matt with 14k hp and the rest with AoE and his mob gang... really overpowered boss IMO, takes more luck than anything else to defeat him, two sentries casting that 85k heaing spell will bring his health back up a notch. Also, if he spawns a monolith, you might as well refresh the page to reload your save game, it's impossible to face those AoE powers while trying to do any substantial damage in time.
This game is very entertaining, the storyboard and dialogues flow very smoothly, just one complain though: you die too easily fighting some of the minibosses at the beginning of the game.
The game's difficulty scaled downwards tremendously compared to Protector III which was a good sign, did not have to play through the same level to grind.
I just completed it, it's not "too hard" to beat it, just need to nail down the strategies (target enemies' weakness) and apply it to the different layouts.
But yea, the point and hero system is pathetic, the rewards are too little and there are too many unit blockers in the maps which just limits strategies.