I see. Really great feedbacks here. Reading it I realized how this game needs a lot more improvements.
I must admit I somewhat noticed the problem with the AK-47 guys. When I tested it I do feel their attacks are indeed too hard to dodge. But are their attacks really do some stunlocking? I tried to make sure to give a little bit invincibility to try to prevent that, and when I tried it for myself I did not get stunlocked... hmm... but I will take note of it.
The exploding bullets... now that you mention it... At first I made it only one bullet, but it wasn't "flashy" enough so I thought I would make it shoot three; then it got too hard so I halved the number of bullets they spawn while also constricting their directions a bit although not completely... I hoped that it would be somewhat more fair but I suppose it indeed isn't fair enough yet. The splash mortar idea sounds like a great idea! Wish I had come up with that sooner... (^.^;
Regarding weapon choice... oh wow I didn't know other players actually felt that way; because when I tested it I actually felt the need to continuously change weapon types. When there are mostly enemies that die with one shot anyway I always use the dual gun mode because I can move quickly. With the dual gun mode I can actually jump over the burst of 8 bullets the AK-47 guys shoot. And the shotgun... I always use the shotgun to fight the boss because it's actually far easier to fight the boss with the shotgun than with the assault rifle due to the limited maneuverability of the assault mode. I think the problem here is with enemy diversity -- I did not make enough enemies, and there should be enemies that encourages speedy maneuver (thus discouraging the overuse of assault rifle mode) and enemies that are far easier to be attacked with close quarter combat (like the boss). I think most of the problem here lies on the enemies mostly attacking with "horizontal projectiles" that require jumping to dodge -- should've added stuffs that for example come from above like for example your suggestion of mortars
Many thanks for the feedback. I will take note of it and may make an improved version of it in a week ;)