Well I spent a while grinding on level 2 until I could afford an AK and I decided you should probably up its damage a bit. As it stands, I actually prefer dual pistols because they are much more accurate and do a lot more damage. And you’ll end up reloading them less often. And what does leveling up do, exactly?
It seems to me in general that you should make all the weapons cheaper or up the money of everything, as well as decrease the time it takes to level up. A game like this really shouldn’t require grinding or anything like that in order to progress, at least not very much of it. You should feel the progression is very fast at first to get you interested, then much slower later on so you’re already vested in it. Like the AK could remain this powerful if you could acquire it by level 3 while only playing through levels 1 and 2 (which means it costs around 15 only!), either that or a level up. That way that as you’re getting to the last level you have gotten enough cash for the 2nd or 3rd best weapon, then you need to grind for the very special ones.
That, or have the tougher enemies drop more money. Or both. And make the money stay a little while longer.