Uhhh...
...Did any1 noticed about how the A.I. fights? (Remember if this does not apply to yours then i don't kno what's wrong) i see that The A.I. fights like chase opponet wherever they go and just don't stop attacking and don't stop chasing unless if found a weapon or powerup that could easily help to kill opponet. >:(
Ratings begin with Addition. Nice Arenas 3+ Level Creator 3+ Quality Option 2+ Cool Weapons 2+. Ratings end with Subtraction. A.I. not so good (For me) 2- Ratings end. Conclusion: The A.I. seems to kno when to activate Shield and they keep Chasing and Attacking me almost all the time overall its not bad neither is it The best but just Good. Hope U can do it real good on the Sequel :)
P.S. or U can at least make the A.I. better.