Are these lyrics grammatically correct?

コンコン、入ってエイスをとらせて
不明の涙はきみの顔を塗る
心はゲエムを終わるを準備
だから諦めて、 MP5を捨ててよ

So I tried to translate some lyrics that were originally in English to Japanese, I wanted to make sure if this was grammatically correct.

I'm afraid it doesn't make sense at all. I can only guess what you wanted to say.

I guess the original lyrics must be the following:

"Knock knock! Let me go in and get the ace
You'll paint your face with tears that don't feel the same
Now Heart Reinforce's up to end this game
You'd better give up and throw your MP5 away"

There are attempts on the web to understand the lyrics and to translate them into Japanese, but they don't really make sense, so I guess it's up to how you'd interpret it.
However, your version is not grammatically correct, if that's what you are asking.

They're more or less grammatically correct, in that they basically conform with certain Japanese grammar rules. As to whether or not they're meaningful or understandable, though, I'd have to say they're not.

They would translate as:
Konkon [which is the sound a fox makes in Japanese], enter and let me take the ace
Unclear tears stain your face
Because the heart is the preparation that ends games
Give up and throw away the MP5

So yeah, the grammar is correct, but the meaning comes off feeling like gibberish.

(continued from above)

Sorry, the translation for the third line would be ore like
Because prepare a game end heart

since the grammar for the third line is clunky.

To ．．．．
You missed the point that this was "originally English" lyrics, which the OP tried to translate into Japanese.

Nope, I didn't miss that at all, and I'm not sure why you'd think I did.

The question was whether or not the lyrics, as translated into Japanese, are grammatically correct. Parts of them are, and parts of them aren't, and many of the parts that are grammatically correct have a strange meaning that's probably not what was originally intended. I figured it would be more helpful to convey what the Japanese lyrics are saying (where they're saying anything) rather than just say "The grammar isn't perfect, so the lyrics are bad."

The question wasn't "Even if these Japanese lyrics aren't grammatically correct, what would you guess I was trying to say in English?"

OK, parts of it is grammatically correct, I admit, but everything put together, phrasing and wording just don’t make sense. I should have said it more precisely, just like you did.

I just don’t think that the fact that it could be translated back into English based on guessing makes it “right.” So I thought you thought that the text was originally written as it was in Japanese and that the OP was asking if this was OK as Japanese lyrics. Apologies for my wrong assumption.

No prob!