Poison damage is 10% of the damage of the hit that poisons the enemy. So if you hit it for 250, then it does 25 poison damage per tick. By that measure, the axe is the best for poison since it does the most damage per hit. *ALSO, ENEMIES KILLED BY POISON GIVE YOU THEIR FULL EXP REGARDLESS OF YOUR LEVEL!* + If you think this is worth keeping alive.
For those complaining about needing to get all the pickups to get 5-stars, you don't need to. If you follow a single route, use anti-friction and not lose it, and time your jumps and dives so that you get most of the coins and kill most of the dinosaurs, you'll get 5-stars for the level. That said, you may not want to use dive attack or slide attack because of the extra X6 they use up. Oh and a slow computer lagging the game may dash all your hopes for those stars.
To give you guys a heads up, you're gonna need guns (well, the rocket launcher) to get through the game, so don't waste points on the other weapons. Also, the rocket launcher has unlimited pierce, so don't waste points on the first row of special effects, either (maybe you need the single pierce at most). And finally, upgrade your base for defense while you reload your guns, and you're ready to win ;D
Easiest way get through this game is use the British. (1) Surround your blockhouse with one layer of palisades. (2) Unlock redcoats, place them on the palisades, and use this until you have enough money to unlock the greenjackets. (3) Unlock the greenjackets and replace the redcoats as you have the money. (4) Expand the palisades in all directions 4 layers deep, and you're set to beat any level. (5) Right before the last wave of a level, sell (click > del) and buy greenjackets until you're out of money for the fastest way to get the half unlock cost for them.
A guide to getting 15000 and beyond: there are two issues you need to deal with 1) not underjumping, and 2) not overjumping. So (1) Underjumping happens when you scare yourself into jumping too early, or you're too focused on perfect jumps. A trick to help this is to cover the left side of your screen with a book or something so that only the tip of the roller coaster shows. Seems crazy, but then you focus only on the important part of the coaster. And then (2) happens if you don't know how to tell when NOT to jump to get to the next platform, so focus real hard on that, and when you get it, you'll have your 15000!
If it helps anyone, so far I'm doing well, made it to level 21 using only the 4 basic spells, plus zues (not sure if that's the best choice for a limit tho). I don't have room to use the level 2 spells at all!