I seem to be hearing that loads of you are failing many missions as marines that I have found to be no problem. In fact I have not lost a marine in either of the first two missions on second or first ed since 2nd ed came out!

The trick is to create corridors of fire for your overwatch. The first part to this is to deploy your marines correctly and also to always assume you'll end up with one command point.

I'll start with a brief description of the first two levels and how I find is th best way to deploy and achieve the objectives.

Suicide Mission.
Start with your sergeant at the front and the flamer to position four, the rest are filling the gaps. Remember you will hjave over a turn before anyone can reach your sights so do not worry about that corridor to the right yet - your last marine will be covering that. You sergeant needs to head forwards and bear left alongside the target room, stopping just past it - it is imperitive you use any command points to get him round the corner as quick as possible though - this is the only killing ground on this mission. the next marine will go straight on and take the last right, stopping just after turning. The third marine goes straight on and stops parallel to the sergeant. With the fifth marine covering the rear, the flamer marine shouldn't even see a genestealer as he walks behind the sergeant a few paces back and then flames the target room.

The new forces make this misison even easier as you can secure areas. First you need to choose who you want to deploy and where - the most important model here is the assualt cannon marine - sure he'll run out of ammo soon enough but he will buy the time needed to get the others to back up positions. He needs to deploy on the room furthest to the left on the map, looking down the corridor. Ensure others can get around and past him. The genestealer player will probably place your sergeant next in the lower room - they always do - he will need to get up behind the assault cannon marine, step around him once the corridor is cleared and then get past the first junction quickly and then walk down and seal all of the entry areas there. On the other side of the board you need to get your marines covering both corridors looking down onto the entry areas ensuring they have use of a full twelve squares overwatch range. if your sergeant was placed here he can hold on til you have moved another man up - you will need three marines on this side - the sergeant can then go help out the heavy and secure that end.
Do not try to secure these corridors as there is too much risk and you can win easily by exhausting the blips as they only get one stack. Any marine in the single-entry room will be best walking forwards to remain parallel with the marine in the adjacent corridor - otherwise he will be out of overwatch range and genestealers can leap frog through his corridor and get closer to the other marine. Any issues during this time and the spare marine can respond within a turn or two from the nearest room to these - you will need a map! Just remember you get to place three of your men and always place first so will only ever have one marine out of position. Cover each other and again this mission is a doddle!