I've been playing for a while, and after reaching Voltage 4, progression speeds up a lot. You earn enough resources to fully upgrade and immediately push through the next 100 waves, so the pacing feels much faster.

However, once you start buying upgrades in batches of x50, performance becomes a serious issue. Even at Voltage 15 (see screenshot), enemies can't actually damage the tower because their damage scales far slower than their HP (4.89M damage vs. 56.60Qi HP). Since they survive long enough to keep piling up, performance gets worse and worse as more enemies spawn.

The strange part is that even though my tower deals more damage than an enemy's HP (6.18Sx damage vs. 56.06Qi HP), I still can't clear them fast enough to keep their numbers under control. I even went back to Voltage 2, Wave 120 because I had missed the Protocols upgrade, and the same thing happened—enemies still reached the tower, grouped up, and tanked the frame rate.

If I had to guess, I'd say the Attack Speed scaling may be the culprit. It actually feels like enemy buildup gets worse as Attack Speed is upgraded. Even outside of gameplay, the game starts feeling sluggish—simple actions like navigating menus become noticeably slower.

Things I like

• The game is genuinely fun. Progression is a bit slow at first, but once you reach Voltage 4 it really takes off, and each new Voltage becomes much easier to complete the next 100 waves.
• Coilworks is a simple and satisfying upgrade system. You can eventually reach some absurd values, that should be capped, like range, at around around 1600 px, you already cover the whole map. 

Things I don't really use

• Chips: Scrap income from Voltages gives so much purchasing power for Coilworks that I don't see much reason to invest in Chips. Gems feel much better spent rushing Blueprints.
• Overdrive: I simply don't have Capacitors to spend here.
• Milestones: Progressing Voltages through Wave 100 (or Wave 300 for Voltage 15) feels reasonable, but the milestones that require reaching Wave 2500 are currently unrealistic. After around Wave 30, the game slows down so much that getting anywhere near Wave 2500 doesn't feel possible.

Things I don't like

• Blueprints: They're tedious to unlock. They take an extremely long time unless you spend gems, and rushing them requires navigating through multiple menus. I honestly wonder how many years it would take to complete them naturally. Once you're dealing with values around 10²¹, another +200% damage barely feels noticeable. In comparison, the Overclock upgrades feel much more rewarding. They're quick to buy, easy to understand, and as soon as I unlocked them I could immediately double every stat. It's a shame they currently cap at 4×, but I still prefer this system overall. Balancing either system at these number scales is probably difficult, but Overclock simply feels better to interact with.

Suggestions

• Add an option to disable enemy animations. At higher Voltages, enemies spawn and die so quickly that you can't even see the animations anyway. Disabling them could improve performance.
• Consider implementing enemy stacking/compression. Instead of spawning two identical enemies, spawn a single enemy with the combined stats of both—or combine any number of enemies into one entity. This would dramatically reduce the number of active entities without changing the gameplay.

Overall, I'm really enjoying the game. My biggest issue isn't progression or balance—it's performance. Eventually the limiting factor stops being the game's difficulty and becomes how many enemies the game can keep active at once.

Thank you, this is one of the most useful reports I have had. You basically diagnosed the game’s biggest weakness for me, so let me go through your points.

Performance. You are right that this is the real ceiling, and you are right that it gets worse with Attack Speed. Your screenshot actually proves it: your Attack Speed is up around 90 shots a second, and every single shot kicks off a little burst of visual effects, so at that rate they pile up fast. On top of that, every enemy does a bit of animation work each frame. Both are fixable without changing how the game plays, and they are my top priority for the coming updates. Your idea to add an option to disable enemy animations is a great call, and I am adding exactly that.

Enemy stacking. I love this idea and looked hard at it. It is a bigger change than it sounds because of how kills, rewards, and special enemies work under the hood, so I want to get the simpler wins in first and come back to it. It is on the list.

Menus feeling slow. Noted, and I have a lead on why. Looking into it.

Range. Great catch, and you are right. There is supposed to be a cap, but I found it is only half-enforced: it stops one source of range but not the others, so with enough investment your range keeps growing until it covers the whole map, which was never the intent. The number on the panel is off too. I am fixing it so range actually caps where it should. Thanks for pushing on this one.

A couple of things that are intentional (so you know they are not bugs): at high Voltages enemies are meant to overwhelm you with numbers rather than damage, which is why they stop hurting the tower and why your tower overkills them but still cannot clear the swarm. The difficulty is the crowd, not the hit. That said, your feedback is making me rethink whether that stays fun at the very top end.

Overdrive, Blueprints, Chips, deep milestones. All fair. Capacitors come in later than they should, Blueprints are grindier than Overclock (which I agree feels great), and the deep Wave 2500+ milestones are hard to reach today, partly because of the performance wall. I am treating these as things to rebalance rather than quick fixes, so they will take a bit longer, but they are all written down.

Seriously, thank you. This kind of detail is gold. Keep it coming.