After having finished my first complete series review (check them out, if you like), I have made it some sort of a good routine for myself to review some sets of my collection in my free time. And with that and my deep passion for LEGO Space, I'll go on to review this space-themed series from the late 2000's.
This set is one of the few sets in this series, that I can fully get behind. It has everything: the looks, the functions, the versatility. And it was the first set for me, where the secondary piece was almost more convincing than the actual model.

Parts

Many large black parts make up the alien fighter. These can be used nicely in MOCs for hull design and shaping something like a jet or a starship. There are also many black blaster guns, like they come to use in many Star Wars sets. Also worth mentioning are a simple bounce-back shooting mechanism and the multi-directional moving joints. Adding to this, there's a medium-sized drill head, an orange dome-shaped cockpit glass and four energy crystals. Once again, this set has an abundance of stickers, eighteen in total. This REALLY is a lot and can be a little annoying

Minifigures

There are four minifigures included in this set: two astronauts, an alien and an alien commander. The astronauts have the usual, detailed printed space suits and some gear, including a large power saw and a small blaster.
The alien is useless as ever, but the alien commander is an interesting thing. It consists of a large torso and head (all with glowing eyes via a 1x1 transparent round brick), the design of which gave me some Bionicle vibes... LEGO shows interesting ways of recycling parts here, since the arms and legs of the commander are exactly the same parts! He has the same hole in his chest as the standard aliens, so he can be fixed to a hold via a stick with holder

The build

Even though the fighter reaches quite a good size when finished, the build is really not that difficult, yet a little repetitive. The wings are identical, only differing in their equipment. There are not really any TECHNIC parts supporting the structure, it's just brick on brick, same goes for the small mining robot. There is an interesting part, where the cockpit of the robot is built, nothing difficult, but interesting. Again, the many, many stickers are a little annoying...

The completed model

The Alien Infiltrator is an impressive air supremacy fighter craft. When in flight mode, is has no less than eight forward facing heavy blaster guns and one flip-torpedo-like shooter (that hardly ever works). The cockpit has room for an alien pilot and the commander, who has an own control panel. It is secured by two large green bars, which can be opened forward. Behind the cockpit, what seems to be a small, drone-like aircraft is attached. The wings can be moved quite freely and brought into various attack positions. The very stream-lined ship can be transformed to a ground vehicle by flipping the wings and folding down the large front part. That way, it stands upright at around 20 centimeters.
The small mining robot has a rudimentary walking function achieved by two turn plates above the legs, the latter also holding some gear. The two moveable arms hold a ground scanner and a drill head. The torso has two forward facing blasters in the front and a lot of additional stuff in the back. A small robot can be attached there as well as a light aircraft. This vessel is completely foldable for minimal usage of space. The dome-shaped cockpit offers 360° sight, unfortunately it has once again no visible controls.

Overall opinion

As one will probably find out while reading my reviews to this series, most of the models have several serious flaws in my eyes and could not reach their full potential. This one here is an exception. Almost everything works with this two-model set: the design is nice, aggressive and intimidating with the alien fighter and sturdy, compact and practical with the mining robot. The functions are neat, the wing movement and transformation with the fighter and the versatility and detachable modules of the miner. Also, the introduction of another minifgure (alien commander) is a good idea, since the standard aliens are so ugly and useless.
One more word on the mining mech: This thing impressed me far more than I would have imagined. Being only the secondary model in the set, it features so many functions and gear and possibilities of playing! The detachable aircraft in the back is so awesome! I mean, look at the mech, it is so small! And then it has an even smaller vehicle as a backpack so that the second astronaut can also go on a flight! And the aircraft is folded up like a baby buggy for optimal storage! Incredible! And that tiny lil' robot! Even cuter than BB-8!
Are there negative points? Sure, nothing is ever perfect. As mentioned before, the mech has no controls in the cockpit. The transformed version of the fighter is good for... what? It surely is no walker, maybe some kind of huge sniper-like cannon for long distance precision shots... The shooting mechanism does not really work that good.
But these few negative points REALLY could not weigh in so heavily for me to subtract from the many, many cool positive features of the set. It's an absolutely awesome space set and an outstanding part of this sometimes so-so series.

really cool and the tiny crystal gathering bot is soooooo cute
exept that each ship in this set has a tiny little detatchable flying object
i am aware though that the one on the alien ship was an attack- thingy
but what was the thing on the back of the astronaut walker? was it an escape jet or something?

This is truly an amazing set. From the streamlined, mysterious design of the ETX, to the advanced driller mech, and don't forgt the tiny Wall-e bot!
Now, to the Pros. and Cons.

Pros.
-Amazing design
-great fun
-MoCing parts galore!!
-Wall-e bot
-mech transformation for ship!

Cons.
-General falls off ship to easily
-stickers..oh stickers how I loath you
-One nudge can tip over the Drill mecha
-Wall-e bot gets lost easily

Overall, this is one really awesome set, and I would reccomend it to anyone who likes each of the following: Spaceships, Aliens, mechs, or Legos XD

this a great set. the mining robot is cool because unlike most other mars mission miners it is not defensless(it has two lasers on the front). the crystal detector and drill are great. the jetpack is cool. also the accessories are cute(it has a blaster, pick axe, and a long drill thing). PETE(Parasitic Extra Terrestrial Eliminator), the human robot is cute an has binoculars for eyes(cough cough walle cough cough). the alien ship is huge! the rocket launcher works well, and it has tons of blaster guns. HARV(Hunter of Astronauts and Robotic Vehicles), the alien minibot, is also cool. the aliens stickers are awesome(they change colors)!

if you can find this set, i highly reccomend buying it.

I picked this up fron S@H for £13, cheap, but I was actually intending to pick this up at full price anyway, so it was an added bonus, and 333 parts for £20 works out at quite a nice price per parts ratio.

Included are 4 minifigs: 2 astronauts, 1 martian and 1 martian commander, who is pretty nice - he's a large, imposing minifig with arms!, also included is a small brick built robot and what I assume to be a martian probe.

The astronauts have a reasonably cool drilling robotic suit, which a very diminutive winged craft attaches to, the crystal detecting device is a nice touch on the suit, it seems Lego has gone the extra mile to create added playability in this set.

The infiltrator itself is large, impressive and bristling with weaponry. Its also worth noting this years martian sets sticker sheets have a nicely rainbow reflective quality, kind of like the rainbow reflections of a compact disc, this adds to the overall classiness of the finished model.

PRO's

• Excellent brick to cost ratio
• 4 minifigures including Martian Commander
• Large and sleek main spaceship
• Generous extra's for the astronauts

CON's

• Firing mechanism on the infiltrator is poor
• slight droop to the front of Infiltrator when nose is up, although its barely noticeable
• Infiltrators walker mode is fairly poor

Overall, I totally recommend this set to any Mars Mission/Space fan and in my view the best of the 2008 Mars Mission line up, so a well deserved 5 from me.