Looking at other posts here I can see that many of you are better players than me.

However, I'm finding World 4 - Level 1 to be extremely challenging and can't finish it.  I get to about the 4th or 5th screen but that's as far as I can get.

Any tips that might help me?

Save your special weapon as much as you can for the last room and blast the boss by entering the final room and moving to the bottom of the screen. Shoot his red bombs on one side only and then destroy him quickly with the last flare of your special weapon.