High Roller Tournaments vs. Main Event Tournaments

Looking around Ignition Poker's tournament page, I couldn't help but notice the buy-in for the Super Million (for example) tournaments. I see:

- Main Event, buy-in $425 + $25, $400,000 guaranteed

- Mini-Main Event, buy-in $100 + $9, $100,000 guaranteed

- High Roller, buy-in $300 + $25, $50,000 guaranteed.

Now I am here trying to make sense about the prize pool of the high roller compared to the main and mini-main events here and I am thinking, "what gives?" Could there be a substantial difference in how the high roller tournament is structured or how players play in the high roller compared to the main and mini-main events? Would strategy have to be utilized differently in comparison to grind my way into the money, final table or if I am lucky enough, first place? I am interested in knowing the difference between these types of events.