TLDR: its fun and given its not very expensive, its worth picking up.
I wont bother going over the mechanics of the game itself, as they are fairly straight forward and the game doesn't really have much depth past them.
The game loop is fairly straight forward, do runs, get coins/items, buy Heroes, buy items, buy guns, repeat. At the start this was pretty engaging, as you can also unlock weapon perks, and work towards the character upgrade, etc. Once I started getting a decent amount of weapons and Heroes unlocked (along with items and consumables) I tried the 'Hard mode' (second mode out of five) and it kicked my butt. It took me several tries to complete a run, by which time I was using some of the mid game weapons and characters, but found that these are not actually that much powerful than the initial Heroes or weapons, bar 1 weapon and 1 character, Zeppelin and Nikki.
I was expecting, given the score based nature of the end modes, that weapons (and to a lesser extent, Heroes) would get, at least, decently stronger than the weapons that game before them, but I found that this was not the case. I found that the later weapons would have only a little better damage, but not by a lot, and the unique traits that came with them were not that strong making some weapons almost unusable unless you get perfect luck in the power ups that you get. I found this quite frustrating, as runs could very easily be decided by luck on hard and, in some cases, normal depending on the weapon, when I felt like the later weapons should give you a decent leg up even if you get bad power up luck.
This brings me to be crux of the issue with this game, balance.
I have put ~12 hours into this game so far, however, I don't feel that much stronger then when I did when I started the game. For me, the Insane mode is easier than the hard mode, as the first boss, The Phantom, is quiet a bit easier than the Collector. I was looking forward to using the later weapons, but I have been disappointed by all of the later weapons when using them. I have yet to really play much of the Dark mode or Endless yet, but I cant see the experience being that different from what I have encountered.
I'm not really sure what the point of all the cool weapons (interesting unique traits and damage styles) is if they don't increase the power fantasy. I would love to see a decent power gradient between the initial weapons and the latter ones, so that you want to unlock them. I don't feel like the heroes need to be changed in functionality, as they do bring interesting play styles to the game, but I would like to see them have less uses and instead have a greater impact when using the 'alt'. With the lack of weapon progression, they can be annoying when they don't feel that impactful.
I really enjoy the art style and game flow, so am hoping the above can be addressed to improve the experience and replay value.
