I've read and heard many criticisms about this game and do not quite understand them. I will try and address them and give my opinion as to why this is probably one of the top three Double Dragon games.
Solid art design, although some of the enemies are a bit more cartoony than previous DD designs, the colors, backgrounds, animations and effects are pretty solid. The game mixes 3D models with the occasional 2D background object, The alley level is particularly nice. Varied environments and enemies with vibrant colors.
Great remixes of classic double dragon tunes and some new additions. Music and sounds are near flawless in this game. Some may loathe the voice acting, but for the tone they're going for, it's appropriate.
The game controls solidly for me. A lot of "Double Dragon veteran" players have criticized how slow and heavy the Lee brothers move, but I think they haven't played DD for a while. DD was always a slower, more methodical game than other beat 'em ups. Neon is actually a little bit faster (go check youtube, watch Super Double Dragon, or DD II). The dodge button is responsive, although you're vulnerable if you execute some moves. The dash is not instant unlike DD Advance and DD3, and that can be a cause for some headaches.
The game has a lot of moves, and some combos . Clever players can find ways to juggle opponents multiple times and incorporate grabs and special moves while doing so. The Lee brothers have mixtapes that grant abilities and special moves like fireballs, hurricane kicks, etc. You can't steamroll through waves of enemies thoughtlessly though, as enemies have some moves with "armor", not many, but it does require some recognition on the player. Players who dodge attacks correctly get a temporary buff. It's a nice addition, though not as satisfying as Super Double Dragon's parry and grab mechanics from blocking.
For Insider: 8/10
I've played every iteration of Double Dragon, even the three fighting games (if you count Rage). I knew exactly what to expect from this game. I give it an 8/10. I've beaten it in normal and Dragon difficulty, working on replaying it again to do so in Double Dragon difficulty (which is quite hard). Highly recommend it.
For Casual: 6/10
Don't even listen or Read IGN's super ignorant review of this game. It's a solid game if you like slower methodical beat' em ups. My wife is an RPG, Strategy game gamer and was able to beat this game a few times with me. She enjoyed the humor and although she doesn't always play beat 'em ups, she really enjoyed this one. 6/10
For newer fans to the genre: 3/10 to 5/10
These fans will probably hate this game the most. If you're used to the speed of Castle Crashers and want to blow through enemies with fast attacks and screen clearing moves this game is not like that. Watch some of the youtube videos for this game, but approach with caution.
** Extras Info
Game's tone is different from prior DD games, at first I was frustrated by this as I wanted a serious DD game, but the game did get more than a few laughs out of me. There are plenty of easter eggs and references to 80s-90s games and culture.