I enjoyed playing the browser version of 3.5, so I downloaded it. I then played a decent amount of it and eventually tried out version 4 build 63. Overall I enjoyed it more than 3.5. Although being able to force a conveyor line to be uninterrupted by using tunnels is something that I sorely miss. I eventually checked to see that version 4 build 64 had come out, so I downloaded that to give it a look.
Build 64 really felt like a downgrade. Sectors was not perfect but it was way better than the new "zones" system and tech tree. The tech tree is just added grinding for resources to arbitrarily unlock "permission" to build things that already had progression in them by their very nature through needing to build up the infrastructure to support more advanced materials and greater energy. After getting the arbitrary permission to build the things, you still need to develop the infrastructure in each match to support them. This is not fun, nor does it add anything to the experience aside from the amount of time you have to dump in to get access to everything. Unlocks and tech trees could be interesting but not when it is implemented just to facilitate more grinding.
I then went to the map editor to adjust my custom map to work on this new version, only to see that all grass textures had been removed. Why? What's wrong with wanting a pleasant environment? Build 63 had a lot of variety in scenery and biomes that Build 64 is just lacking.
Finally, while I am not against the new art style (primarily because the turrets always looked like a jagged mess when rotating to face an enemy), some of the visual improvements from Build 63 seem to have been dropped. The water in 63 was quite nice to look at and the waves were enjoyable. It effectively hid the tile-based nature of the maps. In 64, the water looks awful and repeats far too often to convey anything other than a tileset.
I do not understand the reason for the drastic change between Build 63 and Build 64. Especially in the areas that were changed. What was "fixed" was, most often, not an issue. Aside from elevation, which could have been nice but didn't add much and was visually displeasing. The return of terrain walls is a welcome one. More variety of turrets and explanation on how the ammunitions alter performance would also be nice.
One more thing. I would like to suggest something similar to the "Overdrive Projector" in that they alter nearby structures. They differ in that I suggest they be 1x1 in size and only affect the building(s) that they are immediately adjacent to. Probably requires power to function, and each of them has a limited amount of altering ability that, if touching multiple buildings, it would be equally distributed among them. If only touching one, that building would receive its full alteration amount, of course. The ways they alter the buildings' performance could vary: I would personally like turret-related modifications such as rate of fire, maximum range, aiming speed, accuracy, and the like. Damage, projectile velocity, and extra effects such as Area of Effect and Incendiary would be left to ammunition used.