It's actually way easier to abuse rings in this game for extra lives compared to the Genesis games.
- You get a 1-up at 100, 200, and 300 rings each. (This happened only at 100 and 200 before.)
- After getting hit, regaining 100 rings during the same stage gets you another extra life. (This wasn't the case before.)
- The blue ring item makes it easy to abuse the two previous facts.
If you ever manage to get 300+ rings with a blue ring on hand, just intentionally take damage in a room where it's easily to recollect your rings, and that's another 3 instant 1-ups right there.
Alternatively, you could intentionally take damage every single time you gain 100 rings, as you have the opportunity to regain up to 20 of them, which puts you at 20% progress for the next 1-up.