Great game, despite the fact that you have to grenade jump if an elevator breaks down. I found the ending a bit disappointing - I think there should have been a twist in the plot or something rather than an unexplained pink dragon boss.
Tips for those struggling -
1) Circle them around the map. Don't let them corner you against a wall or a corner.
2)If there's lots them take on one at a time. Don't stop either.
3)Sometimes you have to bite the bulet and run at them, then swerve. If they miss you can hit them in the back, kiiling in one.
4)If you're using a sword and they have a sear then get in close!! Frenzied clicking usually works here(=