Power ups

Spawn locations
Every map has either 3 or 4 power-up spawn locations (except for the EX stages arena and maze with 0, and sky garden with 8. All EX stages however are typically banned from serious play) which will produce a power-up every 20 seconds or so. These power-ups can either give players a small advantage (extra traps, speed bonus), or can dramatically sway the momentum of a match (healer, unit). Since power-ups always spawn in one of these set locations, controlling these spaces on the map is a very important part of high level trap gunner play.

Item types
Extra trap - The most common power-up, gives a random trap to whoever picks it up

Protect - Less common, gives invincibilty for a few seconds. You can use the invincibilty to activate mines/pitfalls/force panels or to attempt to disarm switch traps without fear of detonation

Speed - Gives a speed boost for a few seconds. Useful in chasing down an opponent or avoiding shots/units

Unit - Typically wont spawn until a minute or two has past. Once you pick it up your normal shot is replaced with the unit, which takes a couple of seconds to charge up, and then homes in on your opponent. Unit shots will disappear after a while if they don't hit anything, if the player with the unit is knocked down, and they can also be destroyed by explosions (mines, switchs, bombs). Unit shots can also be avoided by hiding under a bridge/overhang. If you avoid them this way then the unit will destroy that bridge. Unit shots ignore all invincibility.

Healer - Heals a pretty solid amount of health. Less than a unit shot's worth of damage, but since there is no charge time to healing and it can't be avoided in any way a healer can be more powerful than a unit in some match-ups.

Spawn patterns
On 3 spawn stages items will always follow a randomly chosen pattern, meaning you can't predict the first location, the second location has a 50/50 chance of being at either spawn the first wasn't at, the third location will always be at the spawn point that hasn't had a power-up yet.

On 4 spawn stages the pattern appears to be more random, but with more testing it may get more predictable.