Gunner Trapper is a fairly unique tank. Without the assistance of traps, the tank has a thin penetrating offense, a high speed, and a high viewing range. While these abilities are useful, every single one of them is only useful from a decent distance. When using the GT, it is critical to maintain the optimal distance at all possible times. If you back too far away, you won't get any kills. If you get to close, enemies will be able to deal significant damage to you without any amount of speed or sight being useful. Take some time to learn the best balance of offense and defense to maximize your results with the GT. Using the traps is a bit more complicated. The GT user should try to use their traps to buy themselves distance. A wide, distributed field of traps will buy more distance than a tight pack of traps. You can use traps to approach slightly closer to opponents than you could with only guns, this is good for trying to get kills without risking very much. However, the traps are a double-edged sword. They have the ability to buy distance, but they can also lead enemies directly to you. Having a lot of distance is pointless against multiple foes who found you by the fat-ass trail of breadcrumbs you leave everywhere. Therefore, good GT players will make every effort to have unreadable traps. For example, avoid recoiling in a straight line 100% of the time. Once you have escaped an enemy's screen, it is often worth using normal speed to move in a different direction from your line of traps. It is easier to trick enemies by not recoiling when you already have enough traps in their way to let you get off their screen for several seconds. Therefore, make sure to use existing traps to exit enemy screens whenever you feel your life is at risk and you have the ability to do so.
A lot of GT's power is psychological. A single opponent will rarely enter a trap field, even if it is fairly wide. This can often be used to create more distance than you would normally think you could get. However, all psychological advantages become weaker the more enemies you are up against. A team will always be more confident than a soloist, especially if they can see each other. When facing teams, especially ramming teams, attempt to keep the teamers from being able to see each other. This will reduce their likelihood to attempt to push through your traps. Another thing you can do is make actual real traps for teams. Be an artist. Draw hooks and wedges with your traps. If you create dangerous shapes, overconfident teamers will be more likely to walk into their dooms than a soloist. GT's ability to punish enemies who enter their traps is higher than other trappers, and its speed will allow you to more quickly seal off holes that you've tricked people into entering. Consider learning to make traps without firing your normal guns. By doing this, you can sometimes form traps for one teamer without the other teamer even knowing what you are doing.(edited)
Don't be afraid to abuse your scouting abilities. With the GT, you can cover and see more area than an average tank, allowing you to patrol wider trap fields. Make sure to farm whenever you have the opportunity. Farming with the GT is likely to create a naturally well distributed trap field, and also gives you safe spaces to run through when you need distance fast. Avoid moving towards walls, corners, and the center. These areas restrict your ability to get distance for yourself, and you can always make your own walls if you need to corner something without needing naturally occurring barriers that restrict everyone including yourself. Also, creating barriers away from the walls and corners is more likely to surprise players who aren't expecting to have their space suddenly restricted in the middle of nowhere. While in maze mode, try to avoid tight areas that restrict the usefulness of your sight and speed. Since there will pretty much always be walls around, you need to actually use your traps to block areas off more like a normal trapper in order to escape powerful foes that you can't kill directly. Don't stay in a spot for too long, even 2 to 3 uncontested traps in a thin hallway will slow down an enemy for a decent amount of time. Since you may not have space or options to trick enemies by not recoiling, instead make weaving patterns as you run. The time it takes the enemy to pass your traps will be longer than the time you lose placing them unless that enemy is a rammer or skilled fighter. Basically, when in small spaces, play like a normal trapper with some speed. Even though your traps are the lowest DPS of any trap barrel, trappers are inherently better in maze than other gamemodes anyways. There are a lot more small tips and tricks to be said, but I'm lazy so figure them out for yourselves!