There is a problem with the current upgrade system: it's not intuitive. Sometimes when you purchase an upgrade (especially Burst), it actually makes your weapon *worse*. This is unfortunate, because each successive upgrade costs more money than the last.
My proposal: Make upgrades "always good".
In order to do this, you should probably minimize the amount of "penalties" (negative modifiers to weapon variables) that come with an upgrade. The biggest problems with this are the Recharge Rate penalties (adding time severely reduces damage per second, and is the leading cause for making weapons weaker after upgrade), and Accuracy penalties (sometimes the accuracy gets so low (e.g. 20%) the weapon becomes useless and the real-life damage it inflicts goes way down).
While it's possible for you to fix these problems with careful adjustments of balance, this will result in a lot of work for the developers, because they will have to look closely at all the math for each weapon and each upgrade. This micro-management will take a lot of time; probably no one will want to do this. A simpler solution is to try to get rid of penalties associated with upgrades as much as possible. It's important to remember that recharge time is directly connected to damage per second. Essentially, lower recharge time == more damage (and higher firing rate, which is also an advantage).
Another option would be to change how time upgrades work. For example, instead of modifying Rate of Fire in fixed increments (e.g. "Recharge time -0.5s"), you could modify it with percentage values (e.g. "Recharge Time -15%"). This will fix some problems associated with recharge time, and especially problems with combining it with Burst. One of the big problems with recharge time modifiers is that when you use fixed increments, you cause damage per second to increase geometrically for each step that you increase. (E.g. the Particle cannon gets +33% DPS for its first -0.5s recharge time upgrade, then +50% for the second, and finally by +100% when it reduces its recharge time from 0.1s to 0.5s). The fact that the relationship between time and DPS is non-linear and escalating gives the player a disincentive from applying any further upgrades that would affect recharge time, because they would sharply reduce the damage. It's also worth noting that the particle cannon does the most DPS by only applying the recharge time upgrade, and doing nothing else; this is counter-intuitive for the player, who would presume that the "damage upgrade" would be the upgrade that actually gives you the most damage. Changing this to a percentage might allow a flat progression in DPS so that the changes are less extreme; it might also smooth out any problems for when other upgrades add time as a penalty. For example, you could have recharge time upgrades calculate -15% time after all time penalties from other upgrades (like Burst) are calculated, which will reduce interference from those other upgrades.
I would request/recommend, at the very least, that you remove Recharge Time penalties (i.e. damage per second penalties) from the following upgrades, where they are not needed, and cause problems:
- Accuracy upgrades
- Range upgrades
- Hull/Shield Damage upgrades (e.g. Laser Cannon currently penalizes time for this)
In most situations, recharge time penalties are unnecessary. The only time where I think they make sense might be for Burst. In other situations, they cause problems with balancing, and seriously reduce the effectiveness of weapons (sometimes causing the upgrade to make the weapon worse, which is very counter-intuitive!). In general, I would recommend not relying on penalties along with upgrades to "balance" the game, because I think it causes more problems than it solves. Please only use penalty modifiers where they actually make sense.
Finally, Burst is kind of broken. I have done the calculations in a spreadsheet for many of the weapons, and have found that when you buy Burst(1), it often does not improve your ship, or is a painful trade-off (when you take accuracy into account). There are several instances where buying Burst(2) makes your weapon clearly worse, and I would say this makes Burst broken. For a player's fun, upgrades should "always be good". They should not have to do careful math to see if maybe an upgrade they want to buy is going to make the weapons worse.
Weapons where buying Burst(1) makes the DPS worse: Flak Cannon (also reduces accuracy by 20)
Weapons where buying Burst(2) makes the DPS worse, or offers no improvement despite cost: Energy Cannon, Mega Plasma Cannon, Flak Cannon
Note: The particle cannon doesn't benefit from either Burst or Accuracy upgrades because they hurt the recharge time so much that it's not worth it to add even +0.1s.
If Upgrades to Accuracy, Damage and Range upgrades didn't have recharge time (i.e. DPS) penalties associated, this would make it a lot easier to use Burst without fear, because you could compensate for the penalties by spending more money (green tech) rather than adding more recharge time. One of the problems is also that sometimes the penalty increments are larger than the upgrade increments (e.g. for the Energy Cannon, the accuracy upgrades adds +0.3s recharge time, but the recharge time upgrade only removes -0.2s; the upgrade should always be better, I think).
Anyway, that was a lot of info, but I hope I was my writing was clear enough! I hope that you can make the game more intuitive for the players who are not so good at math.
I hope that you simplify the upgrade system so that an upgrade is "always good" and the player doesn't have to think mathematically, but instead just watches the battle and sees the difference (either in range, rate of fire, accuracy, etc.) but has faith that the DPS is higher because they paid for it. I think it would be best to get rid of all penalties/trade-offs, except for Burst, which requires it.
Thanks for reading! I love this game, but I hope you can balance it a bit better. If so, I will keep playing for a long time...
