Before you start: Unlock and buy all upgrades to have a better New Game+ fun

1. When you finish the game, you will be sent to the credits. Skip the credits.
2. Select "Continue" in the main menu.
3. You will be sent to the credits again. This time, don't touch anything and wait for the credits to end. (takes 5 minutes)
4. Select "Continue" in the main menu, again.

Result: You will start a New Game with all of your upgrades and you will get the Web Strike ability from the beggining.

5. When you finish your game, repeat all steps.

Enjoy the game! ;)