Well there's only so much one can do solo in such a short time, so the story dump was fine ^^ same goes for levels even if i'm curious as to what a campaign would be with that gameplay this could be quite cool, and you could keep the arena/horde mode as a bonus mode or something. Oh and i'm sure it's more a time than a skill issue.
Well i don't know much about Unreal engine but from what i've seen the engine seems geared towards super fancy HD stuff so i'd imagine that to make a retro style in it is quite challenging and again i'm sure it's more of a time thing here again.
Yeah tutorials on specific stuff can be hard to find depending on the engine, and i think a great majority of resources around are about Unity since it's the most used and oldest of then engines used by indies.