I think the concept of this game is great. The idea is that it's an open world crime game like GTA, but it's set in video game land filled with parodies of almost any video game character you can imagine. It's a brilliant idea, and fortunately the game mostly lives up to this great concept even if it falls short in some areas.
The game plays as you'd expect out of an open world crime game. However, the game tries to have a much better variety of mission styles. It doesn't try to be only standard A to B shooting. The game tries to mix it up by including missions that are arcade-like or based on old NES games. Thanks to this the variety is incredible and every other mission mixes up the gameplay in some way, so you'll rarely get bored. The quality of the missions do vary however. A good amount of the missions are fun and challenging, but others tend to be a little shallow and funnled, not leaving a lot of room for experimentation. On the whole though, the biggest problem with the missions in this game is that they're all a bit short.
The pacing of the whole game is crazy fast, so it's a very quick experience and missions end quite fast sometimes. Unfortunately this leads to my biggest problem with the game; the main campaign is not very long. You can try to take it slow and try not to rush through, but the game is so fun you won't want to stop. It isn't criminally short though, it can last to about 6-7 hours. Just don't expect a 15-20 hour long campaign. The game offers a challenge and it gets really brutal at times. Don't get me wrong the game is not unbeatable, it's just some of the levels do not hold back on challenge, so there is a good amount of authentic NES-style difficulty. Expect to get a bit frustrated at times if you're not used to that kind of thing.
The game has a pacing problem narrative-wise as well. It seems like the game was supposed to have a somewhat deep storyline and characters but that aspect seems to have been scrapped before the game's release. So as a result, if you were looking for an engaging story, you'll be disappointed. It's extremely fast paced, and has a lot of unrelated events and characters you see once or twice then never again, there's just no focus. That doesn't mean it's horrible though, since it manages to be entertain and the humor is mostly well done. The characters are also interesting and there's always something new and amusing around the corner.
The parody aspect is extremely well done. Basically, the whole world of RCR is one big parody. The characters in it are cleverly de-branded counterparts of famous characters, and basically everything else is a reference to something from the 80's, the 90's, or sometimes the 2000's. The whole city you explore is chock full of parodies and pop-culture references, it's pretty fun to explore. However it's a little 'look but don't touch'. The city is just kind of....there. It's fun to look at, but it's not very interactive and you can't go into most of the buildings. The city is also a bit small as well which is a little disappointing, but understandable if there was not much dev time to spare or it couldn't be bigger due to the NES limitations, possibly both (yes, the game's engine has limitations very similar to the NES). The sprites are small as well which is kind of jarring in contrast with all the amazing pixel art in the game. They're not very detailed, but there is a zoom mode if you want them to be bigger. Just keep in mind that it doesn't make the sprites more detailed, it just makes them larger.
The music in this game is composed by 3 different guys including the legendary "virt" (Jake Kaufman), and they each have their own style. The soundtrack in this game is very, very good. It sounds extremely authentic, so it's almost as if they were ripped out of an actual old NES game. The only problem I have with the music is that during cutscenes, it switches between songs in a weird way. Like one shot shows something and there's a song in the background, then when it changes to a different shot showing something else, it switches to a entirely different song that's completely unrelated to the previous song that was playing, so the cutscenes sound a bit weird at times. Also I know an in-game radio like in GTA is probably hard to code, but in this game you don't get a feeling that it's playing songs on other stations without you. So sometimes, it sounds like it starts playing the same song every time you switch to a certain station.
Overall though, RCR is a very fun and unique game combining all the pop culture from the 80's and 90's into one game, so the nostalgia due to the sheer amount of references gets pretty intense. Also, the game has a lot of variety and and some genuinely good humor, so you'll rarely get bored during the short but sweet campaign. The game may have not truly lived up to it's great concept, but it was pretty damn close. I think there is a lot of potential for this concept, with just a few tweaks, a sequel to this game could possibly be one of the best indie games ever.
EDIT: After some rethinking, I've decided to recommend this game. You have to keep in mind that I waited quite a while for this game, and it didn't live up to the extreme expectations I had, so I set myself up for disappointment. So at first it was more of a personal review instead of an objective one. So I changed it to be more objective and recommended the game. The game still has some hefty flaws, but it's still a fun romp no doubt.