Well, i'm done with the preview server (i did wave 50, but i have frozen missiles on the air and it doesn't end, despite everything is dead...i had this problem on wave 40 too, i had to do it 10 times, finally i got lucky and it ended). if you guys do the second preview and pass wave 50 tell us how it was. Summary:

1 - Scrap snipers are not useful;

2 - Put one shock trooper at bunkers;

3 - fill the bunkers with heavy gunners or suicide bombers. if it's a wave with the v2 tanks, the heavy gunners help to stop the missiles. if it's a wave with a lots of megas, maybe it would be wise to fill with suicides, in case the megas kill the bunker, the suicides kill them;

4 - till wave 40, a higher level can easily do it with 25/30 gatts + 4 flak tanks some suicides and 3/4 other units to help (i had 2 hellfires and 2 laser tanks). you only get some damage on the gats occasionally;

5 - you can check my layout in the pics. i have 6 mortars, 6 lasers, 4 machine guns. the lasers are great cause the units come in bunches...TRY TO USE WALLS TO MAKE THEM PACK TOGETHER...I THINK I'M GOING TO TURN MY 2 INSIDE MORTARS INTO 2 MORE LASERS. IF I HAD PLASMAS 5, I WOULD DO IT PLASMAS;

6 - Not sure if it's a good idea to have base in a corner. sometimes they spawn in range and cause some damage. if they spawn out of range they would probably be killed without damage to you, at least on the first waves. the good thing is that you kill instantly one side of the wave and you can focus in the other sides...

7 - the sides they are coming are random, but by the first side defines the others;

8 - don't think honey badgers are good for this event...that thing of going out with them to kill the v2 tanks...well, 4 honey badgers occupy around 200 of space, with that you can put 2 more gatts and 3 suicides...i think i'm going to scrap them and make more suicides and gatts. i will kill the tanks with gatts, it takes more time but you do it;

9 - i didn't use megas till wave 50...because you need a lot of gats to stops to stop the missiles, kill raptors, hellstorms, cobras, etc...and you need suicides heavily (more than 15/20) after wave 40...

10 - best units for the event: gats, suicide bombers and suicide trucks. 1 shock trooper inside bunkers. flak tanks are useful too, specially at wave 40 were you have the kondor;

11 - best towers: lasers, mixed with mortars. i think machine guns are useful too, to stop missiles from v2 tanks and hellstorm choppers. i don't have plasmas 5, not sure if they work well alone because they don't have splash damage and they have long shooting rate...the waves sometimes have tanks mixed with razors, infantry, etc...that may cause the plasma to shoot at the 'wrong' target. i would do 2 if i had them. you should have some machine guns in the base because of the missiles. i have 4;

12 - maybe using the colossus to absorb fire is not a good idea. megas ignore them till the colossus is near shooting at them. meanwhile they shoot at turrets. suicide bombers seem to be better to absorb fire and they can do real damage to them. also the colossus has a huge repair time. i think i'm going to scrap them for the event;

13 - I DIDN'T SCATTERED SUICIDES ALL AROUND THE MAP, LIKE WE DID IN THE PREVIOUS EVENT, CAUSE THIS TIME INFANTRY SPAWN IN A AWAY THAT I THINK THAT MAKES THIS TACTIC MORE DIFFICULT. ALSO YOU HAVE MORE AIRCRAFTS ATTACKING YOU, SO YOU NEED MORE SPACE FOR GATS...UNLESS YOU GO BACK TO THE MORTAR/MACHINE GUN LAYOUT...THEN YOU CAN HAVE LESS GATS AND MORE SUICIDES...I HAD MY SUICIDES NEAR THE CORNERS AND SUICIDE TRUCKS NEAR CC, IN STAND GROUND. I WOULD TURN THEM TO NORMAL OR AGGRESSIVE AS SOON THE MEGAS APPEAR. ALSO, MEGAS SEEM TO GO FOR THE CORNERS OF THE BASE (MY BASE IS A KIND OF SQUARE);

the point system is different in the preview and probably they will make some changes, but probably you will have XP to have the 2 new units around wave 60 to 70.

bugs i found:

1 - shock trooper shooting at infantry;
2 - units shooting at walls and staying there;
3 - missiles frozen on the sky;
4 - waves 40 and 50 didn't end. 40 eventually ended at the 10th time i did it.
5 - maybe i'm wrong but i saw some infantry that wasn't mine staying alive on the battle field but i couldn't shoot it. could it be units that pop up from my destroyed buildings? i saw some heavy gunners shooting at walls and they would interrupt it to shoot at the flying by v2 missiles...they were rogue gunners?

well this are my 2 cents. hope it helps.

PS - Advice to those who don't have laser turret 5 / plasma 5 or high level gats. maybe the best layout is 10 mortars and 6 machine guns. also build a lot of suicides. i'm talking about more than 100/150, maybe more...build a lot of gatts or hercs too. the problem with hercs is the repair time. also, only level 9 hercules are better than gats in what it comes to damage inflicted (but they have the repair time problem). i think the range of gatts is always superior. you can do to wave 40 easily only with anti-air units and suicides, but you will need a lot, to compesate the lack ok laser turrets 5. the suicides are the guys that you are going to throw against the waves of palladins, challengers, etc...i don't think flak turret is very useful. maybe on wave 40, with the kondor, but i did it with around 30 level 9 gats and 4 level 3 flak tanks. scrap buggies, honey badgers, etc...you can kill the v2 tanks going out with a palladin, for example...