Ps3 – Do challenges eventually disappear in Prototype

If my math is correct you will need 17 923 600 EP

Here is full list of "skill" costs.

Not sure but I think you will need to "grind" some points to get all upgrades,on average you can get over 150 000 points per mission + additional bonuses,with 10 episodes in the game I believe you will still be short some EPs.

Basically two techniques are used. The first technique you probably know where you attack while the sprint button is held down. The biggest speed boost occurs when you attack while running down the hill.

The second technique is when you hold the down button (or holding down on the stick) while jumping. You'll notice in the videos that the characters do a flip when they jump. You're seeing the second technique in action. The jump flipping technique essentially conserves/preserves momentum.

So if you time it right, and speed attack boost down a hill, jump soon after, while holding "down", continue jumping after, and avoiding obstacles while doing it, you can maintain a wicked speed. It takes some practice, but if you can master it, you'll be on your way to the top of the leaderboard in no time.