The game has great potential! Of course it needs more work and polish but I think it’s a great starting point, I can definitely see myself playing this, I love inventory management games (such as Backpack battles).
It took me way too long to figure out that I can expand my slots with the expansion items, as I was mostly looking at the images and quick scanning the info panels. Maybe a thematic item groups would help (for ex. for wheels it works, I could instantly tell what the wheels are, do and their limitations). But for other item families, not so much.
Also, some games that rely on this kind of shop randomness do a clever thing under the hood where they boost the appearance chances for certain items, so you have more opportnities to combine them. For example, I think I got only a couple of level 2 items at the beginning, and then I was just waiting for more of my items so I can combine them, but they never came. And I didn’t have enough space to cram more different items, so from the 1st position I just got lower and lower towards the last runs because I couldn’t upgrade my gear.