INITIAL:
"Gods be praised the enemy general is dead! Fear makes a home in our enemies' hearts!" >>> "χαιρετε, ο γαρ πολεμιος στρατεγος επεσον, και νυν φοβησονται ημας!" = "Rejoice, for the enemy general fell, and now they'll fear us!"
"The enemies flee from the battle!" >>> "Οι πολεμιοι φοβουσιν τηι μαχηι!" (each iota after an eta should be an iota subscriptum - another thing I can't get to work.)

EDIT 1:
"We have taken the walls!" >>> "Ειλομεν τα τειχεα!" To be used in in conjunction with something bound to happen later on (for there's an aoristus and not a perfectum involved here.)
Outro 1 "We achieved a great victory, now it's time to send a messenger to spread the word (of our victory)" >>> "Ενικησαν μεγαλως, νυν δε δει στελλειν αγγελον σεμαινοντα νικησαντας ειναι." = "We've won 'in a great fashion', and now we must send a messenger who will spread the message that we are victorious."

EDIT 2:
Outro 2 (You wanted something a-Vanilla, here you are then) "Bring on the wine, and take care of the wounded." >>> "Φερετε τον οινον και κομιζετε τους τραυματους."
Outro 3 "Let's start looting." >>> "Φερωμεν τε και αγωμεν."
Intro 1 (Vanilla style again) "We should slaughter them from a distance." >>> "Χρη αποκτεινεσθαι τους πολλους των εχθρων υπο των ψιλων, πριν η μαχη αχεται ως αληθως." = "Most of the enemies must be killed by the psiloi, before the battle really begins." The latter part of the Greek sentence could be used for any statement ending with the message "the real fight begins".

EDIT 3:
"Today is a good day to die, but it's better still to live and tell our grandchilderen of our victories" (Vanilla, indeed) >>> “Καλος μεν εστιν ο εν τηι μαχηι θανατος, ο δε βιος τε και ο της νικης μυθος εισιν βελτιοντες.” = "Dead in battle is beautiful, but life and the story of the/our victory are more beautiful." (each iota after an eta should be an iota subscriptum - again.)
"The walls have been taken (by the enemies)." >>> “Ηιρηται τα τειχεα (υπο τους εχθρους).” (each iota after an eta should be an iota subscriptum; due to the way a perfectum is translated this may also stand for "We have lost the walls", for the result of your enemies taking your walls equals (that of) you losing your walls.)
"Our general is dead!!!" >>> “Τεθνηκεν ο στρατεγος ημετερος!!!” (This, of course, can't do without a perfectum so that's why.)
"The enemies are fleeing in terror!" >>> “Οι πολεμιοι ατυζονται!”

Most likely impossible, just wishful thinking on my part; if you could script a general with a hatred for the particular enemies he's facing today to call them "εχθρους" (acc, pl, m) but should he feel no particular hatred for them then he should call them "πολεμιους" (acc, pl, m). Why? Because the former, "εχθρους", may also stand for 'those who are hated' (and therefore probably it came to be 'enemies' as well); whereas the latter simply means 'enemies'.

EDIT 4:
Outro 4 "We have won, and no one can argue about it." >>> "Ουδεις αντιλεγοι αν μη τηνδε νικην ημετεραν ειναι." = "Nobody could question that this victory (here) is ours."

EDIT 5:
Intro 2 "There is no advantage in numbers to either side." >>> “Τοσουτοι εν ημιν εισιν, οσοι εν τοις πολεμιοις εισιν.” = "Amongst us are as many as amongst the/our enemies."
Intro 3 "I have never lost a battle against those people, and why should I start losing now?" >>> “Τι αρα δει τηνδε μαχην νυν πεφυκεναι τραυμα, ουδεμιαν γαρ τινων εμων εκεινοις πολεμιοις μαχων πεφυκεν τραυμα;” = "Why should this battle here result in a defeat now, as none of my battles with those enemies resulted in a defeat?"
Intro 4 "With men such as you under my command." (Could be used in conjunction with other phrases, so I adressed this bit separately.) >>> “Νυν εγω ειμι ο στρατεγος εχων υμας υπο της εμης ηγεμονιας .” = "Now I am the general with you under my command."

EDIT 6:
"Now comes the test of our soldiers courage!" >>> "Νυν δη εις πειραν ερχεται της ημετερας αλκης." = "Now then, is our courage put to the test."
"Now comes the test of their soldiers courage!" >>> (Unsurpisingly) "Νυν δη εις πειραν ερχεται της αυτων αλκης." = "Now then, is their courage put to the test."
Outro 5 "Praise the god of Victory!/Praise the mighty Nike!" >>> "Αινειτε την Νικην!/ Αινειτε την πολλην Νικην!"
"Drive them from the battlefield!" >>> "Εξελαυνετε αυτους παρα της μαχης!"
Intro 5 "If you smell something ripe... that's our enemy! That is what fear does to weaklings." >>> (I completely altered the first sentence, but kept the second.) "Νυν οι πολεμιοι προσωπα χλωρα εχουσιν. Τουτο ο φοβος ποιει τοις αγεννεσιν." = "Now our enemies have pale faces. Fear does that to weaklings" Weaklings may also be read as inferior people, for lots of words in ancient Greek meaning cowards or weaklings may also stand for inferior people. Probably left from their aristocratic days...
Intro 6 "The seer has been consulted but his visions are clouded." >>> "Εγω εξητασα τον ματιν περι τηςδε μαχης, αλλ αι αυτου φαντασιαι αινιγμαται ηισαν/εγενοντο." = "I have consulted the seer on this battle, but his visions kept being/were riddles." Note that again each iota after an eta should be an iota subscriptum.
"Show no mercy!" >>> "Ανευ τινος οικτου!" = "Without any mercy!"

EDIT 7:
Intro 7 "Tonight we will feast and drink, tonight we will tell each others tales of..." + The sentence about enjoying the company of women >>> "Τησδε νυκτης, ευωχησομεθα του οινου τε και των σιτων, και μην ησθησομεθα συνοντες γυναιξιν. Αλλ πριν χρη μαχεσθαι τοις τουτοις εχθροις τε και ελειν το αστυ!" = "This night/tonight we will enjoy wine and food, and on top of that we will enjoy being in the company of women. But first we must fight those enemies over there, and take the place!"
"We have taken the gate!" >>> "Ειλομεν τα προπυλαια!" To be used in in conjunction with something bound to happen later on (for there's an aoristus and not a perfectum involved here.)
"The gate has been taken (by the enemies)." >>> “Ηιρηται τα προπυλαια (υπο τους εχθρους).” (each iota after an eta should be an iota subscriptum; due to the way a perfectum is translated this may also stand for "We have lost the gate", for the result of your enemies taking your gate equals (that of) you losing your gate.)

It only includes words that are used by either Homeros, or Herodotos, or Plato (only his earlier and 'midtime' works), or Euripides, or Lysias and are more than 10 times used in their work + the words that appear at least 15 times in the (combined) works of two of the above mentioned authors, and a few words that were used by other writers such as Sophokles. As you can see, it is first and foremost meant for translating the work of only a few writers.