I've been playing for a few weeks. I started really paying attention to PVP around level 20 (like you guys), and I initially did an overheat build, through level 25 or so.
Same as you guys, I started getting beat up by guys with shields -- it's the Shield Level 3 that really does it: 2 damage per point of energy! Game changing! -- and so I started to work shields into my build. Since then, I haven't seen a strong player who doesn't use shields.
I did pretty well in the 20s (like 10:1 win loss ratio, it feels like
), by using the Yelloworm and various knock-back oriented builds, but around level 29, one guy started wiping the floor with me. He was 4 levels ahead, and he used nothing but energy weapons and the Roman chassis. The first time I saw him, he had 2x Blue Rein and a couple of Zappies. These guns actually drain *more* energy than they cost to use, which the earlier energy weapons rarely do. So it was pretty brutal. He would break my shields and take me apart every game. His build was workable for a few different reasons.(1) The Roman Chassis
The Roman chassis comes out around level 34, and it's just crazy-good. It has SIX module slots! And on top of that, you get to use 4 side weapons (but no top weapons). (2) Improved "Specials" -- double use!
Around the same time, levels 33 I believe, you also get access to the two-use Grappler, the two-use Teleport, and the two-use Charge. This means that it's much easier to get close, even if the enemy has lots of knockback.
I tried everything to beat that guy, but I never managed it until much later, like when he was 37 and I was 35, or something. The level disparities can be very frustrating. I think a good feature would be for the lower-leveled player to get some additional buff (they already go first, but sometimes it's still very one-sided). This could be based on the record of previous games between the two players. Of course, it would be challenging to balance something like this.
Through the 30s, I generally continued playing knockback-oriented builds, with the Big Blue Blast (range of 3, knockback of 2, with good damage) playing a central role. The Yelloworm is still in most of my builds, even though you unlock it at level 23~!! Knockback of 2 is pretty amazing, because if the other guy can't respond from the place that you knock him to, he has to burn one of his actions just to get back in position. At level 39, I can still beat guys who are above you in levels if you bring a Yelloworm and they don't have Physical Resistance.
Anyway, I'm now at level 39, having just got access to the Termination guns - the big fat blue-and-red cannons that work at range 2 and 3, with knockback of 1. I haven't really figured out the best builds at this level. It seems like there's a LOT of flexibility with the Termination guns in the mix, and I'm hoping I can get something that wins consistently, but it's going to be hard. Most of the people above 40 have played a lot of games, and they don't roll over easy.
I'm looking forward to level 43 because when I get there I'll switch out of the Roman chassis, finally. Level 43 unlocks the Flower Power chassis, which has 4 side weapon slots and 2 top weapon slots, 100 Energy with 30 regen, and five module slots.