All thanks to ponypo2001 at x360a
The last mission of the game is accessed straight after finishing Bytanic. Firstly, you need to make your way to the Theater roof. Climb up the ladder on the side to start a cutscene. You will be attacked by two security guards. The best way to deal with any melee confrontation is to block till you feel ready and then press when the enemy attacks you. Larry will slap the enemy as a counter and then you should follow up with one kick by pressing . Repeat this, trying to keep the guards so one is in front and one is behind and you should be fine.
After the fight with the guards, you face Kip. He can hit very hard if he combos or slaps you. Just use the same technique as for the guards. Once his health reaches 50%, he will run off. Now you have to drag the box of fireworks over to the marker and rotate them till they are in the correct position.
Now, Kip moves to Sound Stage 2 roof. Get down quickly, hop in the nearby police car, and then climb to the sound stage 2 roof via the crates. Again, fight the two guards and then Kip will attack you. Use the same tactics and he should run away again. Now, align the fireworks to trigger the final chase.
Now Kip is on the Executive Building roof. Go inside and take the elevator to the roof. Align the fireworks as before and defeat the two guards. Now it's time to finish off Kip. Use the same moves and he'll eat dirt in no time leaving you to breath a huge sigh of relief. The game is over.
PS: If your going to vote negatively at least say why and/or contribute a a solution that you think is better, I put these solutions up because there was none before I did, and they wound up helping me when I saw them on x306a. So if that is not good enough for you the least you can do is make a suggestion instead of voting down the only solution that is available at the moment.