Movio Software Engineer, Backend interview questions

Got a call from HR, was told that they are looking for Go developer and very keen to meet in person to have a small chat. A couple days later, they changed their mind and decided just sent a small test via email - 2 programming exercises ("you can use any lang you prefer"). There were three small questions as well, nothing serious. Next day after test, got their feedback - implementation wouldn’t be the optimal. They wrote that there was a bug as well, but looks like they hadn't even try to launch it (otherwise, it would be obvious, that it works correct).