Undergraduate / I had the idea to rebuild my entire syste - MIT admissions question- significant challenge [5]

The full question is- Tell us about the most significant challenge you've faced or something important that didn't go according to plan. How did you manage the situation?

Below is my current answer. Any advice is REALLY appreciated as I live in the UK so am not used to the US application system.

Over the past year I have been independently attempting to design an 8 bit CPU exclusively using logic gates. I was able to formulate my ideas using a logic gate simulation called "Logisim", a Java-based application. My initial circuits with this system ran well with no faults. It was after I completed the ALU system, or two months after beginning the project, that I started to notice some flaws in the program I was using. Errors started appearing in places they shouldn't have, and the system began running slower. However, I continued work as the seemingly random errors did not have any truly fatal implications. Roughly 250 hours of work and a number of months later, I realised the errors were much worse. I was exceedingly concerned, and so contacted the software developer, a professor called Carl Burch. He informed me that there were some flaws in the program when it came to large circuits- as my CPU contained almost 100,000 components, there was no way I was going to be able to finish. I was sufficiently disgruntled, but decided not to abandon my project and the almost 350 hours I had spent on it. Soon after, I had the idea to rebuild my entire system in pure Java code, using only boolean variables and logical operators. This was a huge endeavour involving changing my own visual idea of circuits to a purely code-based one. It has been three months since I started, and the entire program now contains roughly 15,000 lines of code. I feel like I have achieved a lot, and through continued work and determination, I hope to finish within the next few months.