More ideas:

-Have users fill out a survey when they first use the game to get a sense of their beliefs. The game will then pick a mixture of assertions that they likely agree/disagree with.

-Also, have some 'missles' be actually valid arguments, that give a bonus to whatever missle base they hit if you don't mistakenly try to block them with a shield.

That reminds me a little of the Objection! games. I've played at least one of them and it was quite fun and addictive.

From a review:

In Objection! You deal with a murder trial. With your virtual consciousness at ease you know your client is innocent and have the opportunity to defend the prosecutor's line of questioning by using one of the 12 objectionable categories. The game is not based on memorization, but on learning to identify and understand the proper responses. Many questions are also legitimate and you specify that the question is proper in order to maintain your silence. After every question you can press x or z to get a legal explanation as to the ruling of your objection. They also keep a chalkboard reminder of important tips to remember. As seen below some questions are also worth partial or full credit because a variety of objections may be suitable for the situation. Rulings are regularly updated and it has correct rulings for all 50 states, dc and federal court. You also get the opportunity to cross examine the witness in level 2.

I had a chance to interview a representative from TransMedia the company that makes the Objection! series. The game was originally created for the average consumer, but it quickly became designed for the professional lawyer. Many lawyers have expressed an increased response time and success of sharpening their skills with the game. In fact a Florida judge even ordered some lawyers to buy the game because they were so inadequate at questioning.