but if you want some advice about how to make it better.

You need the rocket to at times catch up with the ninja and follow him very closely in this there wasn't the feeling of direct threat to the ninja from the rocket because it was always miles behind him. If you can manage it its even better when the rocket goes in fount of the ninja I can give you a link for something with this if you want and thereby its path isn't always really predictable. Segments where the ninja and the rocket travel down the same section of tunnel would be nice possibly with the ninja at times letting the rocket through normal doors this sorta thing is fun to see

The ninjas path is not very interesting he should travel through more interesting terrain than just strait tunnels with corners and in most cases there should be other close calls for him apart from the rocket with objects like thwumps and lasers.

Your variety of propulsion was quite good but you could still do more some and it looks as if you descended into launch-pads a bit at the end locked-door propulsion and a few more thwumps would be nice to see in a kradda.

Some more close calls where the rocket passes through tiles would be nice you have one good one but more is better check out this pastebinned copy where I added a couple more and tightened up your tunnels somewhat. http://pastebin.com/m398f9ba6 [pastebin.com]

thats all I can think of right now hope it helps

No real close calls for the ninja but otherwise good

But it'll be interesting to see how you manage to get the DDA to continue.