As a survivor game, this is fun as it allows you to absolutely become a god (and i like being overpowered). My problem with this game is mostly a lack of indicators/hints for things like moving faster in the direction you're facing and the difficulty scaling with distance.
Personally, i don't really like that the difficulty scales with distance as for players who like to zoom through the map immediately (like me), the difficulty can feel unfair without any upgrades and especially not knowing you move faster in the direction of your mouse. Meanwhile, players who prefer to stay around the spawn (to get upgrades quickly for example) won't know that there's enemy scaling. I think this can be negated if the environment shows that you're in a different zone, but i still prefer time scaling since it can be more chaotic and doesn't give you much breathing room once you're overpowered (who needs safety when you have lasers covering the entire map XD).
That said, it's still an awesome game and it gives you the ultimate survivor experience we all love. On top of that, you're not using an engine which is an automatic big score addition in my books. Keep it up ! ^_^