Here's my honest opinion, I am trying to be constructive, not harmful.
The writing is not the greatest. When you have dialogue, maybe have the speaking unit's portrait up, that way I don't have to read "Jim Raynor: <insert text>" I can ignore the bad writing since English must not be your first language, but the portrait would have made the intro at least a bit better.
Right after, I'm thrust into a small squad situation(which I happen to prefer over 'build a base and clear the map' type maps) with Raynor, 2 firebats, 2 medics and 2 medivacs. So, I get 3 attacking units, and 4 healing units. 2 attacking units which by the way, suck VS Stalkers & buildings. Vary the team composition. No medivacs(we just crash landed on the planet), a few medics, a few more marines, and maybe a couple firebats would have been good.
'A Warptor has noticed you!' message shows up on my screen, letting me know that these will keep creating and sending units my way until it is destroyed. I find the Warptor, which happens to be a Warp Gate. When it warps in a unit, there's no animation or anything. A zealot pops up and attacks me, all alone, while his friends stand around doing nothing.
Firebats SUCK vs Buildings. Raynor + 2 Firebats VS 1 Warp Gate. Long drawn out battle of attrition. Not to mention boring.
I finally kill the Warp Gate and I see a Scout! I better get Raynor to shoot at the Scout 50 times.
I find an energy pickup and wonder why it's even there? My medivacs are doing all the healing... longer heal range, move faster than medics... my medics are at full energy. Useless pick up.
I get 2 pings on my minimap, letting me know that TWO Warptors have noticed me... so for the heck of it, I suicide my medivacs just to see what kind of situation I am going to get myself into... a ton of Stalkers, more scouts, zealots, and of course, 2 Warp Gates!
That right there was enough to make me quit Map 1 on the spot. I cannot see myself playing through this map and enjoying myself.
Oh and, I got to choose the difficulty level, and I chose easy, and it seemed to do nothing.
You've got to create a better squad composition, change Warptor to Protoss just on principle because... how can a building notice me? Still some tweaking to be done on Map 1. Now I'm going to go try Map 2.
Same problems with dialogue. Terrible script.
I'm given Tosh, and Tosh only to begin with. He witnesses a Hercules flying, and goes "Looks like someone else survived" and then, when he sees Phoenixes attacking the Hercules, simply says "No." Not "Nooo!!!" as if it's his only way off, but simply "No." at first I was wondering who he was talking too, then I got it.
I'm forced to cloak right away, seeing as Tosh has a Ghost Gun and can't kill a thing with it, and every group encountered is 2 zealot, 1 stalker.
I made my way deeper, and then a cutscene where Tosh can see the top of a Stone Zealot and goes " I'm going to need help to take that out!"
heading down the other path, Tosh gets ambushed by some Hydralisks, and it looks bad, but them some Predators bust out of the woods and kill the Zerg! All of a Sudden, Tosh's 'Spawn Predators' button is unlocked!
At least they're free, and I can spawn 5 of them(easy mode again)... but it takes 5 seconds to spawn them(channeled spell, only spawns on completion), so 25 seconds total for units that can ACTUALLY kill stuff, since Tosh is using one of them ghost guns. Make the ability spawn 5 right away, but unusable during combat.
Scratch that, remove the spawn Predators ability, and give a varied squad count or something that will be fun.
Took 1 minute to kill the stone zealot, because he does 50 damage with Colossus beams, splash, vs my 5 predators. I had to send group 1 in to bring him to half life, then respawn another 5(took another 25 seconds) then send those in to finish the stone zealot off.
I find a Tauren Marine ally. Nuff said...
Eventually I find the survivors of the crashed Hercules, Raynor and Tychus! Tychus gets 'Spawn Firebat' ability! OMG Yay, firebats SUCK vs anything but Zerglings and Zealots! I can spawn 4, which take 10 seconds each(channeled, again).
Try making my way towards a base, and lo and behold, the protoss are allied with Hybrid Destroyers!! Nothing like a crap load of Hybrid Destroyers, Scouts, Immortals and Colossus to really kill the fun!
I must have lost the Tauren Marine in battle bcause it was Game Over all of a sudden! I look at the objectives posted in the top left, and there's nothing about 'Tauren Marine must survive' or even any of the other Heroes.
In the End, once again, work on the little things, increase the fun factor, varied squad composition, and your 'enemy forces' feel very... static. Every group was 2zealot 1stalker until they were just 1immortal and then it started with the Hybrid Destroyer/Immortal/Scout/Colossus combos which just cannot be handled by 4 heroes, let alone with useless summoning abilities which take too much time to get them up. This feels like old SC1 RPGs, follow the path, kill the units in the path, HOPE you live, not because it's balanced, just because you might get lucky.