Tried a little playthrough of this before the Halloween party tonight. I remember it being only a couple hours long when I first played it (plus another two hours to actually beat the final boss), so I figured I had it in the bag.

Thwarted by the mummies in Level 3! You really need that stopwatch, don't you? Interesting choice to make the boss impossible once you pass the stage's final checkpoint. Has anyone here ever done it without it? Those birds beforehand are tough to predict too.

The secret weapon is Holy Water. Makes short work of practically all bosses. Except Drac himself. Make sure you have the Cross/Boomerang for that one.

I've definitely beaten this game before from each checkpoint so it's doable, but the bosses after Stage 2 can be really tough. I'd defer to @GameDadGrant's tips on this one since it's been a minute since I marched through the original CV.