Suggestions

[Johnny Thunder]

Power Tower
Power towers are a huge pain to use at the moment. Since they automatically boost all adjacent towers, integrating them into walls is impossible. Create an option that allows us to make the power tower focus on only one tower. The restriction on only allowing towers to be powered by only one power tower should also be removed. Was quite disappointed that I couldn't create one super tower. More variety never hurts.

Link towers
Both link towers are horrible. The main issue is that they are way too expensive.
Damage link - Nearly all the area towers I unlocked will hurt nearly the same ammount of units for far more damage.
Slow link - I unlocked them because I was expecting at least 90% slow and maybe as much as 95. 80%? Frost towers miss occasionally, but frost towers don't cost me 140 coins just to fully cover 1 square either. Either seriously boost their slow or cut their price in half. Preferably the latter, slow link is useless in early game, which means I have to give up a tower for a possible late game advantage, except that means either go without a slow tower for the early game or give up firepower, and neither is worth it when frost towers do the job just fine.
Link towers create additional pain when it comes to integrating them into mazes. I can't have mazes that run along the edge of a map because of them. I can't create 1 square wide zig-zagging paths. This diminishes their already low value.

Sonic tower
Crap. Splash area should be increased considerably. Currently I can barely get it to hit a couple of units as streams of them run past it.

Oil tower
Crap. 60% slow at level 3? Should either be 80 or have much bigger range/splash area.

Slowing in general
Stop lower slow towers from overriding better slow. I'm not sure how many towers this is an issue with but the machinegun definitely disrupts other slow towers' function.

Tower targeting
I'm a bit surprised this wasn't in already. Allow us to select priority targets for towers. I really hate watching hordes of next to no HP fieldrunners get by just because the tower is stuck on stupid. Strongest/Weakest/Closest/Fastest/Slowest/Air at a bare minimum.

Sandbox mode
Would make testing/experimenting a lot easier.

[Fraser]

Good suggestions. Tower targeting would quite fundamentally change the game so not sure they would consider implementing it (it would stop the game being so passive though, which I think would be good on PC). Being able to manually assign towers getting a boost from Power Towers would be awesome though. I never use them as they are too difficult to incorporate into your maze. I am guessing they were intended to be used with Railguns, but no one uses Railguns anymore since the splash damage was nerfed..

My biggest gripe with the game is that the towers aren't very well balanced and most to them are comparatively useless to the few good ones. For the most part I never change my loadout between levels unless there are fire or radiation immune enemies to consider.

As I see it the only viable towers are Gatling Tower for wall building and early game damage. Machine Gun in addition maybe if you can spare an extra slot. Ice Tower for slow. Spark Tower for early to mid game damage. Radiation Tower for mid to late AOE damage, and / or Pyro / Boomkin Tower depending on infantry resistances. Tesla Tower for single target and end of maze damage.

Once you have unlocked all the above there’s no reason to use any other towers. The Spark Tower is cheap, does good early to mid AOE damage and gets you loads of combos early on. It makes all the other early game towers not worth considering, even ones with big ranges like all the missile type towers and Laser Towers.

Once you unlock the Ice Tower that's generally the only slow tower you will use. It renders the more expensive Oil Tower completely obsolete. The Machine Gun and Glue Tower can still be somewhat useful on occasion as are cheap, but rarely can you afford to have two slots taken up by slow towers.

I have not unlocked the Slow Link Tower yet but can see it being a waste of time much like the Link Tower due to cost of needing two. The standard link tower defintely needs a massive hike in damage to be viable. For the cost of building and upgrading at least two of them they should instakill infantry until well into mid game, especially since you cant increase DPS with slow towers.

[Talus]

Sorry for the necro but just got this game through Humble Bundle and you already touched on a suggestion I was about to make: enable tower targetting priority! So many other TD games include this feature that I was surprised to find it missing here. Nothing fancy, just the standard set: "closest, farthest along, strongest, weakest"