I like the idea of this being a deck builder built out of cassets. It’s a cool idea. The visuals are also great and the music is quite engaging.
What I really miss are some sound and fx effects for the attacks and car movements. You already have some cool move and attack animations and the fact that the car placements are matter adds to the game depth. But the Boss fight in it self does not feel particularly exciting because of the missing effects. I think you could tweak that to have a much bigger impact. So you actually feel like you driving the car and get rammed and so one.. like camera shake and some particle effects could really add to the dramatics.
The deck builder screen could really use some explanation how to choose the cassets. I mean I found the way it is meant to be used, but it took some time and caused some minor frustration, but again that would be easily fix, just add a little text and/or arrow to the left where the cassets should be placed and gg.
The cassets by themselves are quite okay, but they glitched quite a lot while fighting the boss, as hovering over them didn’t show the tooltip most of the time.
Oh and please add a fullscreen key or button as I had to play in browser resolution and had to scale down to actually see the whole game.
But other then that you have a great game on your hands and could very well extend it with contend in between the bosses like Mad Max style fights in between, gathering resources / cassets, etc. Could be very cool.
Job well done!