Let's see... To start things off, you did mention the TNT and instakill drops, so imma scrap that, since TNT nukes all zombies that spawned (and if you're lucky, you can advance to the next round no problem) and instakill basically makes zombies one shot. There are four more power ups, like Double Points, Free Mystery Box, Max Ammo (only drops every 6 waves), and Carpenter (the floating Diamond Axe).

Double Points essentially gives you twice the points for every zombie kill (but to make things more satisfying, zombie headshots are the way to go).

Free Mystery Box basically spawns a mystery box that hasn't spawned in that area you're currently in (for example, say the box has spawned somewhere far, like Prison or Cave, that's when this power up comes in handy) because mystery boxes tend to spawn far at most and sometimes near Pyramid or Village, depending on how lucky you get, and instead of paying 950 points, you pay 10 points instead, so get to spending before it vanishes!

Max Ammo replenishes your ammo if the server host changes the limited ammo when they start it up to True. But that only works if that setting is implemented at the start, and if ya like a challenge, go for it.

Last, we have Carpenter, that floating Diamond Axe. It does its thing by repairing all barricades that have been broken already by zombies, but it does help slow them down a little.

But I do agree that we need like some sort of power up explanation somewhere at the spawn area, so new players in Oasis can get used to the mechanics. Anyway, I do hope this helps out! - Soru

gotcha the mystery box one was the one i had no idea was going on mostly and the axe one as well, usually not near a barricade when it spawns.