Here comes Constructive Criticism!
Oh.My.GOD! How I hate this game! It's utterly horrible! Let me give a detailed list of explanations why your game sucks in my eyes!
-Your jumps have to be very precise.
-Blocks play such a major role in this, that you MUST have your shell. In the original side scrolling Mario, it was no big deal if you couldn't break blocks or not. Here, your shell is like God's Blessing.
-Having your fire button as the same button as the run button was kind of convenient. Never got me killed, but it's plausible. Your jumps have to be very precise. You're also quite an asshole for just putting flying Yoshi's there, so people think: I must jump on that to get across. But no, you can just Super Jump across, in any form.
-When you try to jump on enemies above you, you either die or lose your upgrade, and then die. Take that stupid bird on level 2 for an example, at the start. If you're below it, you don't have to jump on it, but the reason why it's there is to get jumped on from lower ground. You could actually jump over it if you were on higher ground.
-Since these conveniently located flaws usually kill you in the start, what's the point of "continuing"? Just go to the map screen, reload your game, and start over without losing a life. Utterly stupid.
-In the Thwomps section, you can't actually run past them while they fall. That's right. Then again, they're slow enough, so I'll give you credit for that. Nice job on pissing the shit out of me for that one. I was pretty close to the end.
I couldn't even get past level 2. The ONLY re-deeming aspect of this game is that you put SO many secrets in it, I can actually get by with all of them at my disposal. Not to mention your one up system sucks. Normally, in the original Mario brothers, you could walk BLINDFOLDED, and get a 1 up from the excessive coins. Here, it's just pointless as shit. I used that system once, and ended up in the middle of level 2, no shell, 3 lives. Now refund my 2 hours of life spent. Normally, I can beat any game, but this game just sucks too much for me to actually beat it. I Wanna Be The Guy was okay, but this is worse. It's majorly horrendous. Fix these flaws come back later, and show me a better game.