i liked it, but i have a few small gripes,
first, there wasn't really much of a challenge, as even if you got road that didn't fit, you could just place it somewhere since you usually have a lot of connections leading to nowhere and with rotation almost any road piece could fit anywhere you wanted
and second, an ingame tutorial would obviously be nice to have and also keybinds for the different road pieces so you don't have to keep moving your mouse to the bottom of the screen
but it's really cool for a first game! good job