Yep, there are a number of ways in which you can set up the G25C2 to meet your needs.
The four normal modes are obtained by loosening (starting from high) or tightening the head. Starting from the head being tight, you loosen the head just a little to get the second mode. Turn it further to get the third mode, and further still to get the fourth. Reverse that motion, tightening the head, to go back through third, second and first mode.
The first option you have is to choose between 'Tactical' and 'Regular' mode. Tactical mode has turbo and medium as the first and second mode, with the third and fourth modes being different strobe modes. In Regular mode you have turbo, high, medium and low.
You have the option of setting the power switch so that a 'double-tap' activates strobe.
Alternatively, a quick loosen and tighten of the head will activate strobe. Repeating this motion will cycle through a number of different flash patterns. If you then loosen the head, the light will go to level 2, and then you can tighten it to go back to level 1. The instructions actually state to twist the head to position 3 or 4, then back to 1, to activate strobe, by I find speed has more effect than position. If I twist the head back and forth quickly, I'll get to strobe, without worrying about the position too much.
So, depending on how you set the light up, strobe is never too far away, if you want to be able to access it easily.