Stage 1
Pretty straightforward. Watch for the boss's dash attack in the second phase. Maybe stay further away, or on the platforms
Stage 2
Go for research center. After jetpack guy, watch for sudden spread shot on right side.
Try waiting for the hands to smash, then quickly dodge to the side. Either that, or already be on the wall before the smash?
Stage 3
Use bomb on trash monster. First attack is high, then move positions, then tail sweep.
Taurus boss will eventually keep charging in one direction, so you'll need to get past him.
On tank form of boss, normal attacks don't hit easily. Either time laser hits, or save the homing shot.