Just Fired - Any Help From The Masses?

I was recently fired from my job for poor performance (in Indiana).

A week before the firing, I was told they were unhappy with my performance and offered me 2-3 months for me to find a new job or improve. I informed them that I appreciate it and would not be offended if they looked for another applicant while I continued to work for them. We all knew I was unhappy because I wasn't able to succeed in the role, even given the extra work I put in and time spent. (I was told months before this (2 months before, of the 8 I held the position) that I needed to improve. I did, and was even emailed saying that I had since brought my "A Game" and everything is good.)

The following week--last--I was abruptly let go and offered a part-time position at the company instead. I of course took this role, as I need a job, but now I want to know of my eligibility for full unemployment benefits instead.

I have not received anything in writing about being fired (no cause or reason) or of this new role and what is required of me. Nothing in writing as to pay, hours, or job responsibilities, etc. Only verbal.

I do know that my employer was not happy with my performance, but it was my understanding that others in the same role as I were having issues with performance as well. Until the week before I was fired, I did not know that I would be fired (although I often joked about it to close co-workers).

Do I have a chance to gain full unemployment? Anyone else in a similar situation before? How did it play out?

Welcome Acets114.
 You might have a shot at unemployment.   I don't know the rules in Indiana but I don't think it hurts to try.  Read the Indiana Unemployment website and see what applies to you.  You might get lucky and actually find something useful.  
 You still have to report your part-time income but you might (or might not) receive an additional check from unemployment.  
 Good luck my friend.

as long as you did not engage in willfull misconduct, you can be considered poor job fit.

a company needs to document misconduct, and it need to have documentation that you had Numerous warnings

file and appeal if denied

Good luck. Wouldn't hurt to try to get unemployment