This game gave me more than my expectation.
Gameplay - Gameplay of is pure fun. Plenty of fun to make gun shoots & use power. One of the strong aspect of this game is it's open ended. Which has taken the game to a new dimension from the 1st one. Various items can be collected throughout the game like Gold, Intelligence, and Tomes of Power to buy weapons, power upgrades. Another good thing is you will achieve 4 types of different power. Powers like - Ability to go though secret areas, see enemy weak points. see enemy through wall, become super powerful, block enemy bullets, make the enemies fly, ability to throw up a shield that block, ability to slow down time etc. There are different groups, for them you will have to work to make the places free.
Story - Only downside of this game is story. Lame story like Nazis are making super soldiers & creating portal. You will have to stop them. Quite simlar like the first one.
Gfx - Gfx a bit outdated. Still it was OK with me.
AI - Ai wasn't so tough as the 1st one. Another downside.
Gameplay hour - Gameplay hour is perfect. Took me about 8 hours to complete thsi game,e. If you explore more then it will mostly take about 10 hours.
Boss fight - Have lots of boss fights. Most of those was good. Last boss fight looked lame to me. It was easy & lengthy.
Difficulty - I played in normal difficulty. Looked easy to me. So better to play it in hard mode.
Optimization - Game is heavily optimized. Not so much noticeable bugs, glitches.
Overall my rating is 8.5 out of 10.
One tip, if you play this in hurry then you wont get the full fun. Play it slowly with full attention & try to explore all areas.