Create mock retro computer system that users can interact with

I'm creating an escape room which will have a retro computer system in it that users can enter answers into and get a result.

There may be multiple answers to input, so there would be a menu screen first and the user would press a number to choose which answer they want to input, for example the options may be "1. Core Temp, 2. Safety Level, 3. Working Height etc. etc." underneath it will say "Select a number to input that answer". When they press the number it takes the user to an answer input page where they can enter an answer, or "press backspace to go back to menu". If they enter correct answer it displays message and possibly a barcode image, if incorrect it goes back to the answer input page.

Ideally I would like the ability to change the menu text, and answer messages so I can change down the line if I wanted to, but if this is a lot more work then I'm happy to decide up front all the text and never change it.

Design wise I want it to look like an old retro computer program - commedore 64 style, but maybe a little more modern so it's all clear and easy to read. The system will be called "Training Simulator Input System".

I want the user only to have access to a keyboard, and as before only be able to access this program, with a way for us to exit and shut down etc.

If you can create this please let me know rough cost to do so.