I beat Valis 2 in one game today.  The last time I played it was a few years ago and I recall levels 4 and 5 kicking my ass.  Today I went in with full powerups and the sword wave projectile that nullifies enemy projectiles, took my time, and made it through without a problem.  
Hilariously, I died on the 3rd level boss right after I killed him and the game let me start on stage 4 with all of my powerups intact.