Wow, very astute question. Yes, I think you should ensure correctness.
The sentence fragment above is an example of an incomplete sentence that nevertheless expresses a complete idea in a way that is easy to understand. Even though I am a professional English editor, I still do not know how to explain when and how it is appropriate to break the rules of grammar!
You are so smart to ask this question about changing the rules of grammar when doing a presentation... Really, I think the only way to learn which grammar violations are acceptable is to examine the grammar violations you see in other presentations (made by people who know how to make great presentations).
If you are not confident about violating the rules of English grammar effectively, then I think the safest thing to do is adhere to the rules of grammar as well as you can. I always recommend a tiny book called The Elements of Style (Strunk & White). This book can enable an ESL student to use English more powerfully than most native speakers. Having perfect grammar is not as important as understanding the psychology of language.
Student or Learner