Just downloaded the game today and put about 3 hours into it... and I have kind of a mixed bag about it. At first, I found the game to be pretty simple, as all you really need to do on the novice setting is just spam the Kick Button until people die, but then I got to the bosses... to say it simply, they kicked my ass, and I have begun to notice some problems I have with the game. First of, the game never goes into detail about any of it's complexitys like what items do, how to equip items, and most importantly, there is never really any set direction to go. Granted, it's an NES game and a lot of games at the time had a whole exploration aspect to them (Zelda and Metroid), but I feel River City Ransom doesn't do it as well as though games. On top of that, when you die, you have to fight the bosses you beat ALL OVER AGAIN! Why? Could you imagine if Zelda or Metroid made you refight the bosses when you died? What else is really depressing is when you die for the first time, you think the game has a checkpoint system, but no... it just takes away half you cash and resets all the bosses. There are a couple little things that bother me, like how you can damage yourself by running into walls or running off cliffs that are right at the beggining of screen, and hurting yourself because items bounce off walls and getting gang raped by thugs who surround you.
To say the least, it hasn't really aged all that way well, but most of my complaints are common with a lot of NES games at the time. However, my biggest complaint about the game is just how grind heavy the game is (or so at first). Since the game doesn't tell you what items do and it just tells you how you need to get stronger, you are forced into farming for cash on easy enemys so you can aquire power-ups that don't always give you what you need, which then has you farming agian to buy something different and when you find that magic item, you then need more money so you can buy more of them, so you grind some more... you see where I am going? This is also my exact complaint with Earthbound, because both games have a create combat systems and are fun to play, but the grinding just slows down the pacing WAY TO MUCH! It's just really anyoying and granted, the combat is a lot of fun, but that is to much, and if you die on a boss, guess what? You need to beat the bosses again, so you grind some more to get ready to beat that bosses. I feel they put the whole RPG element in there mainly because they wanted something to suck up time.
A while back, I once heard a wise man discuss the major differences and flaws between Castalvania 1 and Castalvania 2: Simon's Quest (Which also has a crap tone of grinding) and he as well hated the grinding in the game. His responce was the fallowing, "Let me ask something? What is the difference between: a) killing a bunch of zombies to collect a bunch of hearts, collecting the hearts out of them so you can buy an item to get to another part of the game and b) playing a game where you kill zombies that try to stop you from reaching the end of the game? Answer: 4 HOURS!!!". I feel the same way with this game. They force you to grind so you can basically gauntlet through the rest of the game, when they could of just avoided that and put more work into creating memorable and unique levels and focus more on the smooth combat and better boss fights, instead of making you take ages to get you character up so you can attempt to take on the rest of hte game. To be honest, the game demands a lot from you and the reward isn't that great.
After about 2 and 1/2 hours of grinding and failing at the bosses (which are pretty cheap in some case), I jumped on youtube and found a really helpful game guide and after playing for another 30 minutes, ended up finding the game to be a lot more enjoyable. There are two ways to make this game a lot shorter and take out all of or some of the grinding: 1) Grind a bit in the beggining so you can buy the Dragon Feet (BEST ITEM IN THE GAME) and make your kick EVEN MORE AMAZING and just race through the rest of the game buying some power-ups along the way (takes about 20-30 minutes), or 2) Put in a code that gives you all items and max stats and beat the game in under 12 minutes. The second one is cheating, yes, but the game is so much better when you don't have to worry about leveling up your character (which is also pretty flawed as you level up off random item effects), and you only need to buy health and heal items. Personally, I think this game caters a lot more to that play style rather then making you take ages to do what you want.
Overal, despite it's flaws, there is a pretty solid brawler under the hood. The combat is pretty fun and can be deep once you aquire the other items, and the game had a lot of ground breaking ideas for it's time (A pretty solid game world and a pretty big focus on exploration), but it just doesn't bring it all together properally. It's a nice try, but other games later did this much better.
Sorry for the novel, but I had quite a bit to say about the game xD.