Great Thing is a tough act to follow, for sure. His Darius Gaiden incarnation certainly livened things up, but in-between, he was still in a class of his own. There were more vicious or more carefully planned attacks, sure, but his withering wall of fire was quite unique. Come Darius Force, we have Great Force. Heavily armed he is, but not so meancingly as his predecessor.
Pow pow pow blam blam. What more can you want?
Tips: True to form, Great Force sprays you with bullets from dorsal cannons. Following this, he moves up, his big cannon charges up and, well, does its thing. He moves down and forward; if you stay in line with his cannon, a hatch behind it fires a missile which splits into three smaller (destructible) warheads. Moving more to the left, his rear cannons kick in. Two batteries fire up, while a more vicious (rotating) piece of artillery fires destructible mortars which erupt into pillars of flame when they hit the ground. A bit dramatic, isn't it? Besides that, the dorsal cannons fire some pretty good seven-bullet arcs.Great Force then moves back to the right, and a single dorsal cannon fires at you again.
On facing you again, the cycle of attacks more or less repeats itself until everything has been blown off (the missile launcher at the rear being a bit tricky). At this point, Great Force starts firing large and fast spitball-like shots from his mouth. The wicked mortars kick in as well, but the spitballs are your only real concern. There is a long enough gap between the mouth opening and him firing, so that shouldn't be too much of a problem.