I beat it on Easy with all three characters.
This would have been a really good game if not for the terrible hit boxes, especially against one particular boss, and a couple other issues. I tried unsuccessfully about a half dozen times on Normal difficulty with Adam, making it to the final boss a couple times, before dropping it. The boss where the hitbox is the worst is the one that breathes fire from his mouth. While it clearly represents the flame shooting down and away from him, it's almost like the hitbox is the entire rectangle, meaning that while you should be safe by being "above" or "below" the flame, you'll actually be hit. Another big issue I have is that you can't attack while on top of a weapon lying on the ground. Rather than punching the enemy, you'll try to pick up the weapon. This also means that you'll be switching weapons if you're carrying one. What makes this even worse is that weapons disappear after being dropped or laid down a few times. There were many times where I wasted weapons due to repeatedly switching weapons with what was on the ground instead of attacking, causing them to magically disappear. It would be nice if the characters could have some sense of urgency and be able to run. It also would be nice to be able to jump and move along the Z-axis, rather than only left and right. It might make sense for the arcade version, but keeping the time limit doesn't make sense to me. I only ran out of time twice, and for it to do nothing more than making you lose a life really doesn't make sense.
I liked the music, which I've heard/read gets generally positive mentions, and there is some serious bass in a few of the tunes. It's nice that there are noticeable differences between the three characters beyond how they look. Being able to call the police car to deliver a special attack to one-shot all non-bosses (although having this work on Stage 7 is comical) is neat. I read that they improved the voice samples for the Sega CD version. It also seems like they removed all cheats for this, as I tried every one I came across online, and none worked. I mostly wanted to use them to try to get the bad ending.
I really wanted to like this, but the negatives prevented that. I think the Sonic's Ultimate Genesis Collection (PS3) release has save states, so I'll likely use them to practice against the bosses that give me issues and will probably be able to beat it on at least Normal difficulty.
Update:
I went back and beat it with all three characters on Normal. I realized a way to deal with the fire-breathing boss, and had gotten to where the twin female tumblers boss was manageable, and got by on my first try with each character. I tried once unsuccessfully on Hard, making it to the end boss on my last life, but was tired of the game to try any more.
