A trading tecnique would have to be highly ineffient to prevent 6 card from getting you an deck in the game. Also a "shop" type trading system would prevant donor files
The computer's capabilities are challenging but it use a playing style I have never seen before. Also the computer always uses that style. It would be remarkably easy to create a program that always beats yours but never a human. If someone were to create a chess program that an self-adapting playing style so that it could never be beaten the same way twice I would be very impressed.
4/5 good concept and execution, unconventional, all in all a great game. The only annoying thing is when you reach a certain level you cannot combo quickly enough. Maybe reduce fuel loss in the air and compensate by increasing it on the ground?