I have a Real time always on screen, but I didn't really check for the IGT, nor do I really know how to calculate it. Can I submit my full game run or am I screwed?
The IGT is posted at the end of every level, so you can scrub through and calculate it yourself and you can use this document to help https://cdn.discordapp.com/attachments/617791724818792476/857349790933450792/Ultrakill_Timing_tool.xlsx . Although only the real time is technically required to submit and the verifiers are going to have to calculate the IGT regardless. In short, you're fine. If there are any problems your run will be rejected with a message on how to fix it, so it's no worries.
If you have not seen ULTRAKILL is finally having a speedrunner competition for real money!!! It starts in about four hours from the time I am making this news post, in fact its probably already started when you are reading this so click the challenges widget on the right and read up on the rules and