Why does dragon age 2 cheat at parts?

So ive been playing dragon age 2 and have noticed a pattern in improper leveling and enemy design. has anyone else had problems with the game cheating? it sets rules that u must play by like stamina magic health and basic physics and constantly breaks its own rules. for one i noticed at 3 major points only, like the giant dragon, sir templar on anders quest, and last straw quest with blood mage and shades. all having the same shitty qualities. there are way to many enemies that fight unfairly and use abilities that rnt seen or contract the rest of the game. the rest of the game is fun and has challenging parts but is pretty consistent, but these parts are not. they were made improperly and i can tell because i have done everything on my side to ensure my success. i am at the highest level, ive done all the quests, have all companions at max levels and and have outfitted myself and well as companions with best equipment, and have put runes, extra spell, and poisons on everything and everyone. i am just playing on regular too mind u. I also looked up guides and strategies to fight against these and the game defies what they say in the strategy . the rest of the game i go thru without restarting or dying except these 3 parts in which i die 99/100 times. is it a flaw in the game? i pause right before i die and notice over 20 enemies+ even after i took out a lot of the enemies, and each time they do attacks that defy the graphics such as automatic 180 or unstoppable and odd attacks that seem like someone digitally spitting in ur face, attacks hitting even when no where near, counting attacks as casted even thow they didnt work or use of health potions but no restoration of actual health and just plain dirty attacks that would be considered below the belt in any other circumstances. I just wanted to know how many others have struggled with these three parts. because the rest of the game has been pretty cake but it just seems to bottle neck at these parts and makes the game undesirable and leaves me discusted with the people responsible for this mess. it just seems like negligent game designing from the fat virgin game developers. i know its hard to make games and i accept inevitable flaws but with this aspect simply is unacceptable. sry ithis is kind of a vent to stop me from filling my game case with anthrax and resending it back to their studio with a **** u note attached to it. they made mass effect 2 one of the best games ever and to see this is just pathetic. just laziness and ignorance.Why does dragon age 2 cheat at parts?
Try it with different companions and try it on easy,it worked for me.