Surprisingly difficult. In-run upgrades are meaningful and enjoyable, however they need more variety. Roguelite, out-of-run upgrades are almost non-existent. All classes feel varied and unique. Shooting feels good, the headshot, spray deviation, and heat mechanics all add substance. Weapons don't necessarily feel balanced correctly (I feel as though some lower rarity weapons are quite a bit stronger than their high tier counterparts), however they do feel unique enough to warrant each player having their own preferences. Difficulty modifiers feel challenging and aptly rewarding. Enemy variety isn't massive, but they all have extremely clear visual language and are distinct enough to be very fun to engage with on a gameplay level. Zero issues with visual clutter or performance issues.
The UI needs a passthrough for clarity; for example, Pulse Kick and Seismic Impulse (two abilities on the Demolisher class) say they remove "additional plating". In the tooltip, Seismic Impulse states it removes 2 plating, while Pulse Kick doesn't say how much it removes. Similarly, the description for Pulse Kick has a plating icon next to the word, while Seismic Impulse does not. These small discrepancies are everywhere. Another example: you can purchase something that adds a perk to your weapon; however, if you have 4/4 perks, it replaces one, without warning, without saying it will do so, and without choice as to which one. Outside of this, the actual UI design is, uh, clearly made in Unity (derogatory)
Another bit of feedback: the end run screen should let you hover your abilities, perks, weapons, etc., to see their total uptime, usage amounts, kills, accuracy, etc.
