I really like my beat em ups, hense me liking MK a lot. Maybe it's cos Im use to highly technical beat em ups like Tekken & Capcom Vs SNK 2, but I found MKDA very disappointing. Here's my reasoning for why Im not enjoying it.

Graphics:
The graphics are the best part of MKDA, with nice character models and arenas. The blood is also mightilly impressive.

Gampeplay:
MKDA is the most simple 3D beat em up I have ever played (except maybe DBZ Budokai). The controls are so basic that it removes a lot of depth in the gameplay. I like my fighters technical, and MKDA sure as hell isnt. The moves range from basic single buttons to an attack + a direction. With the likes of Tekken and VF on the market, I fail to see how such simple gameplay can compete. Added to this are the 'dial-a-combo' moves, which add a little bit of depth, but not enough for my taste. I cant believe I read about people on this site having difficulty with some of them.

AI:
The AI sucks ass. The computer is ok at easier levels, cos it lets you hit it, but at higher levels, I found the computer had automatic responses to many of my attacks. For example, if I go low, the computer instantly blocks low. If I jump attack, the computer counters with a move the overides jumps. This (for me) takes the enjoyment out of a lot of single player matches.

Characters:
The characters look different, but all their moves are pretty much the same. Despite the stance system, theres no diversity between the martial arts, as each command list is virtually identical to any other stance/characters. In addition to this, most the attacks look identical, for instance, all the high kicks look the same for each character.
This in turn means that despite there being 20+ characters, theres very little diversity between the characters, leaving little point in learning to play as different characters. The attacks themselves dont have very much 'omph' to them, mostly looking like prods rather than viscious attacks.

Fatalities:
The fatalities are disappointing too. Even the 'better' ones are unoriginal and boring after seeing them 3+ times. In addition, performing fatalities is ridiculously easy.

Lifespan:
I respect the designers for trying to enhance the 1 player experience with Konquest and the Krypt, but even they loose there entertainment value after a while. Konguest lacks depth, and the prizes in the Krypt are usually unrewarding.

Sound:
Screams and music are also good, and I hope in MK6 they expand on this by giving characters unique voices.

Overall:
I can understand a lot of people enjoying this game, but the actual gameplay lacks so much technical depth that I was very disappointed, as this is the main source of lifespan and entertainment for me. Back to the shops for MKDA, and back to better beat em ups for me.